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Project title: Protected Ornamentals: The efficiency of water use in different production systems

Report: Final Report (December 2000)

Project number: PC 166

Project leader: Mr Tim BriercliffeADAS Park FarmDittonAylesfordKent, ME20 6PE

Key workers: Mr Tim Briercliffe (Project leader, lead author and researcher)Mr Neil Bragg (Project planning, data collection and contributing author)Mr Stuart Coutts (Project planning and data collection)Mr Harry Kitchener (Research for Section 5, author of Section 2.2 and crop quality assessments)Mr Adrian Jevans (Author Section 4.2)Dr Tim Pettitt (Author Section 4.3)Dr Ian Clarke (Statistical analysis of crop quality assessments)

Location: Commercial nurseries across the UK

Project Co-ordinator: Mr Andrew FullerW. J. Findons & SonsBordon Hill NurseriesBordon HillStratford-upon-AvonWarks

Date commenced: 1 July 1999Date completed: 30 September 2000Keywords: Water, fertiliser, environment, run-off, protected

ornamentals, nitrates, phosphates, open and closed production systems, environmental legislation.

Whilst the reports issued under the auspices of the HDC are prepared from the best available information, neither the authors nor the HDC can accept any responsibility for inaccuracy or liability

for loss, damage or injury from the application of any concept or procedure discussed.2000 Horticultural Development Council

No part of this publication may be reproduced in any form or by any means without prior permission from the HDC.

2000 Horticultural Development Council

CONTENTS

Page

Practical Section for Growers 1

1. Introduction 7

2. Overview of Research Work and Practices in Water and Nutrient Use in Ornamentals2.1 Review of Experimental Work2.2 Review of Practices in Water and Nutrient Recirculation

9

3. Evaluation of the Efficiency of Water and Fertiliser Use in Different Production Systems for Protected Container Ornamentals in the UK3.1 Materials and Methods3.2 Results3.3 Discussion3.4 Options for Improving Efficiency

20

4. Water, Irrigation and Run-off Treatment Systems Costings4.1 Water Costs4.2 Irrigation Systems Costings4.3 Water Treatment for Preventing Disease Spread - Methods and Costings

51

5. Legislation and Practice in Other Countries5.1 The Netherlands5.2 Germany5.3 Australia5.4 USA

59

6. Existing and Proposed Legislation in the UK 65

7. Conclusions and Key Recommendations 77

8. Acknowledgements 80

9. References 81

Appendices (listed on next page) 85


Appendix Number

Title

I Specification for Concrete Floors

II Stage 1 Irrigation test results

III Water Quality for Stage 1 Nurseries (Untreated Water)

IV Water Quality for Stage 1 Nurseries (Irrigation Water)

V Water Quality for Stage 1 Nurseries (Run-off Water)

VI Average Particle Size Analysis and AFPs for Stage 1 and 2 Nurseries

VII Quantity of Water Applied in each Nursery to each Plant in Stage 2

VIII Profile of Water Use on each Nursery in Stage 2

IX Light Levels Reaching Stage 2 Nurseries

X Water Quality in Stage 2 Nurseries (Nursery A)

XI Water Quality in Stage 2 Nurseries (Nursery B)

XII Water Quality in Stage 2 Nurseries (Nursery C)

XIII Water Quality in Stage 2 Nurseries (Nursery D)

XIV Nutrient Content of Tested Plants in Stage 2

XV Plant Nutrient Content and Application of Liquid Feed in Stage 2

XVI Leaf Tissue Analysis in Stage 2

XVII pH of Irrigation and Run-off Water in Stage 2 Nurseries

XVIII Mean Sieve Analysis and AFP Results for Stage 2 Nurseries

XIX Plant Quality Scoring for Stage 2 Plants

XX Breakdown of Irrigation Systems Costings


PRACTICAL SECTION FOR GROWERS

BACKGROUND AND OBJECTIVES

Growers are under increasing pressure to improve the efficiency of water use and reduce losses of fertiliser to the environment. These pressures include the high cost of mains water, environmental legislation, customer demands and environmental responsibility.

UK growers are not unique in the pressures that they face. Growers in some European countries (e.g. The Netherlands and Germany) have to deal with very strict legislative controls in place to protect the environment. In these countries growers have to demonstrate that the production systems used do not lead to environmental pollution. Some States in the USA face similar pressures and in many regions of Australia growers are having to reduce water consumption. Lessons can be learned from these countries even though UK growers are not yet facing the same environmental pressures.

This project aimed to enable UK growers to compare different irrigation and growing systems in order to help in the selection of systems that reduce water and fertiliser wastage, help meet customer and accreditation demands and comply with legislation. The project also aimed to provide growers with costings information to compare systems for irrigation and run-off treatment as well as to identify targets for future research and development work.

SUMMARY OF RESULTS

Evaluation of the Efficiency of Water and Fertiliser Use

The research was divided into two stages. The first stage was designed to assess the variation in efficiency between a range of different production systems and the second stage was designed to quantify water use and loss throughout the Poinsettia production season for four selected systems.

Stage 1 The primary objective of Stage 1 was to establish the degree of variation of water loss between and within different growing systems. Seven production systems were identified as being the most widely used for the production of protected ornamentals. These were as follows:

‘Ebb and flow’ flood benching Overhead gantry (application usually to capillary matting) Hand-watering (using hosepipe) Capillary (various systems using capillary principles) Drip / trickle Overhead spraylines Trough track

2000 Horticultural Development Council 1

Nurseries using these systems, for the production of Poinsettia were identified and an ‘irrigation test’ was carried out during week 38 of 1999. The irrigation test consisted of calculating the quantity of water applied to a measured batch of plants and then calculating the quantities of water actually taken up by the crop and the quantities unused. In nurseries that were not recirculating water the quantities unused were assumed to be lost to the environment.

AFP (air filled porosity) and particle size tests were carried out on the different growing media used and water samples (untreated, irrigation and run-off water) were analysed at each nursery for nutrient content.

The chart below shows an estimation of what happens to the water applied to each Poinsettia pot in the nurseries tested in one irrigation cycle.

Key to abbreviations used on the graph: Ebb = Ebb and flow benches (recirculating systems) Cap = Capillary matting systems with varying water application methods Tric = Trickle irrigation (dripper to each pot) Trough = Trough track Hand = Hosepipe watering Spray = Overhead spraylines

Fertiliser losses and costs for the whole growing season can be extrapolated from the data collected in Stage 2. For example, nursery Cap B2 looses over £450 worth of fertiliser (450 Kg) for every 10,000 plants grown. This compares to nursery Cap A1 loosing £60 (60 Kg) and nursery Tric A2 loosing less than £10 (10 Kg) worth of fertiliser, through the season, for every 10,000 Poinsettia plants grown.

Stage 2This stage further developed the work in Stage 1 by identifying four nurseries and measuring water and fertiliser usage throughout the whole Poinsettia growing season. The four systems tested were as follows:

A Ebb and flow flood benches 10m2 (recirculating). Flood for 12-15 minutes per irrigation.


B Flooded capillary matting on benches (recirculating). Water is released onto one end of the bench and allowed to flood the bench. Capillary matting on the bench helps to retain some water after the flooded water has drained away.

C Plants standing on open mesh benches overlaid with capillary matting (‘fleece’). Irrigation is applied by an overhead gantry with nozzles directed beneath the foliage to the matting.

D Plants spaced on heated benches overlaid with polystyrene overlaid with polythene overlaid with capillary matting overlaid with perforated polythene. Irrigation is applied by a hosepipe with lance.

The chart below shows what happened to the water applied to each plant in the four systems tested in Stage 2.

This chart clearly shows large variations in the quantities of water applied by nurseries A-D to a standard crop. However, real water losses only occurred in systems C and D as systems A and B were recirculating. The cost of the water and feed applied in each system can be calculated based on a standard proprietary feed cost of £1/Kg and a water cost of £0.67/m3. The costs for producing 10,000 plants are shown below:

£/10,000 plantsNursery Cost of

water applied

Cost of feed

applied

Total cost of applied water and

feed

Cost of water lost

Cost of feed lost

Total cost of unused/lost water and

feedA 66* 44* 110* 0** 0** 0**B 25* 46* 71* 0** 0** 0**C 51 50 101 31 23 54D 63 100 163 15 57 72

* Uptake only as the rest was recirculated** All water and feed was used as the system was recirculated


Nursery B is the lowest cost system to run, in terms of water and feed costs. Although water and feed was not lost from the system in Nursery A, the input costs were relatively high due to larger quantities of water used by the crop.

Guideline costings were produced for ten different systems on an example one acre nursery. A summary of these results is shown below:

System Set up cost per m2

(£)Annual running cost

(£/m2)Ebb & Flow Floor (Recirculated) 28.60 0.51Ebb & Flow Floor (To waste) 27.80 1.12Ebb & Flow Benches (Recirculated) 33.29 0.48Ebb & Flow Benches (To waste) 32.39 1.00Gantry 23.18 0.67Overhead 1.71 1.01Hand-watering 0.46 1.38Capillary Matting 2.24 1.02Drip 2.92 0.39Trough Track 26.63 0.83

It is recommended that growers read the full report, showing the assumptions made, before using these figures in project planning.

Options for improving efficiency of water and fertiliser use

For many growers a complete change to recirculating systems will be impractical. For this reason this project has assessed each of the currently used systems to see how they can be modified or what practices can be applied to make them more efficient.

Ebb and flow and trough track systems should be designed with built-in recirculation. Water tanks (containing liquid feed) should be allowed to run down to low levels before emptying out. These are high investment systems but have many additional benefits, including increased throughput and improved crop handling. They are commonly used in The Netherlands, Germany and Denmark and have a place for quality crop production.

Capillary systems should apply water ‘little and often’ and ensure the use of high quality level matting. This research highlighted the different ways that different people treat capillary systems. Nursery Cap B2 had the same system as nursery Cap A1. The only difference was that Cap A1 turned the water supply on for 9 minutes and Cap B2 turned the water supply on for over an hour. Nursery Cap B2 could easily change practice to dramatically improve efficiency with no cost to crop quality.

Drip systems offer good water saving potential for pot production as long as drippers are regularly checked. Nursery Tric A2 only lost 11% of the water applied compared to the capillary systems, most of which lost over 80%. Drip irrigation works well for


pots 1 litre or greater in size. They would be impractical to install onto smaller pots and packs.

Hand-watering systems can be efficient if supplemented with capillary matting and careful application by trained staff. Nursery Hand B (nursery D in Stage 2) is an example of an efficient hand-watering system where careful application to capillary matting over polythene on benches only lost 8% of the water applied. In contrast nursery Hand C lost 78% of the applied water. There is a high labour cost associated with this method of irrigation and as labour supply becomes harder to find growers should seek alternative irrigation methods

Spraylines are difficult to improve and inherently inefficient. Careful choice of nozzles can help to reduce the loss of water onto paths. These systems should be used as little as possible and alternatives should be sort when installing new systems.

Gantry systems provide well targeted water application. Shutting off nozzles irrigating hard surfaces can reduce wastage.

Avoiding Pollution

In most cases (except for the recirculating systems) the water that was not used by the crop was lost as run-off from the glasshouse. In the case of most systems the water seeped into the ground beneath the structure or drained out of the end of the glasshouse. Where these glasshouses are located near to watercourses or sensitive groundwaters then there is the possibility of water pollution for which a fine could be charged if discovered by the Environment Agency.

Legislation in the UK

Fertilisers are rarely applied directly to soils in protected ornamental production but there can still be considerable run-off of nutrients to the ground. The area under protection can become a point source of pollution, possibly exceeding agricultural levels. Therefore, the following aspects of legislation should be considered:

Water Resources Act 1991 - follow the new horticulture sections in the MAFF ‘Water Code’.

Groundwater Regulations 1998 - Ensure that these regulations are complied with and listed pesticides and fertilisers are only disposed of onto authorised sites.

FEPA - Prevent water contamination by pesticides by following the regulations. Drinking Water Directive - Ensure run-off is not causing nitrate levels in adjoining

watercourses to exceed the limit of 50 mg/l nitrate. Water Abstraction Licensing - Obtain a copy of ‘Taking Water Responsibly’ (from

DETR) and plan future abstractions and water uses in the light of these proposals. Nitrate Vulnerable Zones (NVZs) - Growers of container ornamentals do not come

within the scope of NVZs but growers within these areas should aim to minimise nitrate leaching to avoid future legislation.

Horticultural enterprises should be seen to be minimising nutrient and pesticide run-off in order to prevent the imposition of heavily enforced legislation in the future.


Action Points for Growers

It is recommended that growers calculate their own level of efficiency of water and fertiliser use. This can be done by following the procedure below:

1. Select a production area that you would like to test and calculate the number of plants in the area.

2. Weigh 20 plants, immediately prior to an irrigation, and record the weights.3. Attach a water meter to the irrigation system (available from LBS Horticulture or

LS Systems) to measure the quantity of water applied to the test area. In some cases it may be difficult to attach a meter in which case an alternative method of calculation will need to be used.

4. Apply the irrigation and record the quantity of water applied.5. Re-weigh the 20 plants 30 minutes after the irrigation. Note that longer may need

to be allowed for crops grown on capillary matting where water uptake takes place over an extended period.

6. To calculate the quantity of water applied to each plant divide the total quantity of water applied to the test area by the number of plants in the test area.

7. To calculate the quantity taken up by each plant subtract the pre-irrigation weights from the post-irrigation weights and calculate the mean uptake.

8. To calculate the quantity of water lost subtract the quantity taken up by each plant from the quantity applied to each plant.

Once this calculation has been done the system should be assessed, with staff involved in irrigation, to formulate a strategy to improve efficiency. The system can be re-tested later in the season to assess progress. In addition growers can carry out a simple water audit of the nursery to assess the potential for collection of roof water and run-off for use in irrigation. This may include a feasibility assessment for slow sand filtration or other forms of water treatment. Some key points from this research are highlighted below: Capillary irrigation systems are not necessarily efficient in their water use. Their

efficiency depends on how they are managed. This research has highlighted the value of ‘little and often’ water application on capillary systems.

Drip irrigation is very efficient and the costs of installation and management may not be as high as many growers would expect.

Growers should assess whether they are compliant with current environmental legislation and implement measures to ensure they continue to be.

Growers should analyse water quality to assess the content of the irrigation water and run-off leaving the site.


Anticipated Benefits

Making the relevant changes to production systems can greatly reduce water and fertiliser losses. The research has shown the potential cost of fertiliser losses and highlighted that it makes sound economic sense to assess current practice. By making simple changes, as recommended in this report, growers can reduce water and fertiliser costs, ensure legal compliance, keep within the requirements of the ‘Water Code’ and become more ‘environmentally friendly’ and therefore more likely to satisfy customer demands both now and in the long term.


1. INTRODUCTION

Growers are under increasing pressure to reduce water and fertiliser losses. These pressures are from four main sources:

Government legislation Customer demands and accreditation schemes Rising water cost Environmental legislation and pressure groups

Until now the main pressures for any auditing of business processes have been from retail customers, particularly the major multiple retailers. Cost has also been a driving factor for growers reliant on mains supplies where water costs can be greater than £1/m3 in some regions. However, growers are now facing pressures from legislation. Growers abstracting water from surface water or boreholes will need to justify their water use and demonstrate efficiency to be allowed to retain abstraction licenses. In addition, pollution legislation is likely to affect growers with nutrient-contaminated run-off if the industry does not act now to improve efficiency.

The objectives of this project were to quantify water and fertiliser losses from different production systems by carrying out efficiency tests on a number of UK nurseries growing Poinsettias during the 1999 season. These tests involved single irrigation measurements as well as detailed monitoring of water use on a number of Poinsettia crops throughout the whole production period. Poinsettias were selected as a relatively standard crop grown on a range of systems over a long production period.

The objectives of this project were:

To quantify water and fertiliser losses from systems used in the production of protected ornamentals

To outline clear measures for improving water and fertiliser use efficiency To aid compliance to legislation and reduce the likelihood of rigid future

legislation To compare costings for different irrigation systems To enable growers to implement simple measures to improve practice

Wastage of water and release of fertiliser to the environment cannot be justified and most growers can implement simple measures to greatly reduce losses and in turn reduce the threat to the environment.


2. OVERVIEW OF RESEARCH WORK AND PRACTICES IN WATER AND NUTRIENT USE IN ORNAMENTALS

2.1 Review of Experimental Work

Comparing and Improving System Efficiency

Considerable amounts of research have been carried out in countries where growers are coming under pressure to reduce water and fertiliser wastage and losses. These countries include The Netherlands, Germany, Denmark, Israel, Australia and certain states within the USA. The issues faced in some of these countries are outlined in Section 5. Much of the recent European research has been based on ‘closed’ production systems. This is due to legislation imposed to eliminate nutrient run-off from nurseries as described in Section 5.

Most UK growers should be considering how they might reduce wastage of water and fertiliser and the first step should be to improve their irrigation system. Many European growers have eliminated this loss of water to the environment and are now looking at how to reduce water and fertiliser use by the adoption of ‘closed’ cropping systems.

Water Use Efficiency

Work in Australia (Hall et al., 1998) compared levels of leachate leaving the following different irrigation systems:

a) Constant flow capillary matting (drippers constantly applying water)b) Intermittent flow capillary matting (cycles of 4-6 minutes/hour for 12 hours

followed by 4-6 minutes/2 hours for the next 12 hours)c) Ebb and flow (flood to drainage hole height 2-3 times/day)d) Overhead sprinklers

The following plant species were tested: Artemesia ‘Powis Castle’, Coprosma kirkii, Rhagodia spinescens, Hebe traversii and Heliotropium arborescens ‘Lord Roberts’.

Between 55 and 79% of the water applied by overhead sprinklers left as run-off. The recirculating systems saved 40-46% of the water that was used in the overhead system and this would have increased to 60% if the tank water had not been emptied between trials. There was little difference between the intermittent and constant capillary systems which had similar water uses to the ebb and flow system. The Artemesia and Heliotropium grew better with the sub-irrigation systems but there were no quality differences with the other species.

Morvant et al. (1997) compared capillary matting, ebb and flow, hand watering and microtube (drip) irrigation. Pelargonium hortorum ‘Pinto Red’ were grown in 15 cm pots (1270 ml) with three plants per pot. The water applied and run-off produced was recorded as shown in Table 1.


Table 1 - Water applied and run-off produced in systems tested by Morvant et al. (1997)

Irrigation system Applied (L) Run-off (L) Run-off (as % of applied)*

Hand 148 52 35Microtube 108 48 44Capillary mat 278 88 32Ebb and flow 116 8 7

*Column added by author of this report (not in cited reference)

Run-off was clearly highest in the capillary system and lowest in the ebb and flow. The microtube system showed a relatively high percentage of run-off even though total volume applied was comparatively low.

These systems were tested again by Morvant et al. (1998) under two watering regimes. Each system applied water at a daily regime or an intermittent regime (i.e. water applied as required). The plants watered daily were bigger and more lush but the quality was generally lower because the growth was weak. The daily regime used more water than the intermittent one due to higher evaporation levels. The intermittent system was more efficient with water use but the run-off produced contained higher nutrient levels. The hand-watering system produced shorter plants than the other systems and 33% of the applied water was lost as run-off. Capillary matting also showed a poor efficiency of water use and this was attributed to evaporation from the mat surface. This system is likely to be more efficient in regions where temperature and light levels are lower. However, cooler climates can also promote algal growth and encourage infestations of sciarid and shore flies on such mattings. The study concluded that nutrient-rich run-off is best reduced by daily irrigation with ebb and flow or microtube systems but that in areas where water shortage is the main concern then intermittent microtube is the best option.

Irrigation frequency has been investigated in a number of projects. Work by Tyler et al. (1996) compared ‘little and often’ regimes to those with fewer, more prolonged waterings on Cotoneaster and Rudbeckia. Cotoneaster plants were grown in 3.8 litre pots and given the following treatments:

a) 900 ml once/dayb) 450 ml twice/dayc) 300 ml 3 times/dayd) 150 ml 6 times/day

On the cyclic irrigation regime a one hour break was allowed between each watering. Treatments b-d showed a 38% improvement in application efficiency over treatment a. However, this work was carried out in the south east of the USA where temperatures can be considerably higher than in the UK.

Work by Groves et al. (1998) on the same crops showed that frequent water applications (2-3 times a day) of small volumes can improve irrigation efficiency by


27%. With this greater control of watering, CRF (controlled release fertiliser) levels could be reduced.

Current research at HRI East Malling in a MAFF Link project (number 201) aims to improve the control and efficiency of water use in container hardy nursery stock. The research has subjected three species, Forsythia, Cotinus and Hydrangea to water stress treatments. Results so far have shown that it is possible to achieve a 50% water saving (i.e. 50% of normal evapotranspiration) without reducing crop quality. Most UK nursery stock growers irrigate at 300-400% of the evapotranspiration demand (Cameron, pers. comm.). This research is demonstrating that there are potentially huge water savings that can be made in nursery stock production. The main limiting factor at present is that most nursery stock growers do not have the technology and facilities required to control water application in this way.

Reducing Fertiliser leaching

Reducing fertiliser leaching can present a problem. It has long been recommended that growers water pots with 10-15% more water than required to prevent a build up of nutrients in the container (Cox, 1996). Most growers probably considerably exceed this and therefore there is still potential for reducing this excess (leaching fraction) without risking salt build up. Schuch et al. (1995) indicated that fertiliser application to Poinsettias can be reduced by 50% by reducing fertiliser application and controlling irrigation.

Andersen and Wang Hansen (2000) grew Weigela ‘Bristol Ruby’ and Campanula carpatica ‘Dark Blue’ at three different ECs (electrical conductivity):

High 2000 S/cmIntermediate 1250 S/cmLow 950 S/cm

Weigela were grown in 3.5 litre pots at a spacing of 11/m2 and Campanula were grown in 0.67 litre pots at 40/m2. The ECs of the compost solution were measured three times each week and the feed adapted accordingly. Fertigation was initiated when three of the five tensiometers used reached 50 hPa. Fertigation was applied for one minute. The nitrogen uptake by the Weigela crop, in the low and intermediate ECs was so efficient that N levels in the leachate were reduced. Only 3-6 KgN/ha were leached from these treatments compared with 40 KgN/ha from the high EC treatment.

N leaching from the Campanula crop was much higher, with leaching of 90 KgN/ha from the high EC treatment, 45 KgN/ha from the intermediate and 17 KgN/ha from the low EC treatment. These higher levels were due to greater N leaching during flowering when N is not taken up.

The only quality effects noted in the work were that growth was slightly limited in the low EC treatment on Weigela. The best fertigation treatment produced only 1.5 -10% leaching compared with 22-56% leaching observed on the same crops grown with CRF outdoors.


Controlling Water and Fertiliser Application

There are many ways of controlling irrigation and feed to ornamental crops. The work cited above shows how different uses of the same system can greatly improve efficiency. The research carried out in this project has shown large differences in watering efficiency between growers using similar capillary systems in the UK. The research shows that ‘little and often’ irrigation is often the most efficient use of water and leads to minimal leaching. Large infrequent applications tend to be very wasteful. For example Otten et al. (1999) tested the effect of fertigation frequency in ebb and flow systems. They found that the time Ficus benjamina plant roots were kept under water had little effect on actual uptake. Most water was absorbed within the first five minutes and there was no difference between flooding for five minutes or 30 minutes. Watering twice a week for 30 minutes was insufficient and watering four times a week for five minutes was far more effective.

Evapotranspiration was measured and it was calculated that 19-41% of water lost in evapotranspiration was actually lost in evaporation. Temperatures and light levels can have a significant effect on water use. With a knowledge of evapotranspiration levels as well as ‘actual buffer capacity’ (as defined by Otten et al. 1999) then minimum fertigation requirements for a particular medium can be defined.

Some workers have tried to produce models for irrigation requirements for specific crops, as Stanley and Harbaugh (1989) did for Poinsettia. However, although most tested varieties responded well, not all did and most growers would be reluctant to adopt a model that may not work on the varieties they grow. The measurement of soil moisture tension has already been referred to with the use of tensiometric equipment. If standards could be produced at specific tensions, in different media, for different crops, then there would be considerable potential for water and fertiliser savings.

Newman et al. (1992) used solid state tensiometer technology to maintain soil moisture tension at 1-5 kPa on Poinsettia ‘V-14 Glory’ over a 10-week period. Drip irrigation was used and the controlled plants were compared with plants grown with drip irrigation but based on a manually operated system. There was a 65% saving in the total water used in the computer controlled system and a mean weekly reduction in leachate of 98.6%. There was no measurable reduction in plant quality even though compost analysis showed higher EC levels in the plants held at 1-5 kPa.

The tension of 1-5 kPa is very low compared with other experiments where tensions have been imposed up to 18 kPa. Hansen and Pasian (1999) showed that water application to container-grown roses can be halved by keeping crops at medium tensions of 7-12 kPa compared with low tensions (i.e. 3-6 kPa). The tensiometers were not as effective on plants grown at 15-17 kPa and these high tensions seemed to produce a lower quality crop.

Work by Werkhoven and van Os (1998) and recent unpublished work by Voogt et al. (in press) used Time-Domain Reflectrometry (TDR) and Frequency-Domain (FD) dielectric sensors, in addition to tensiometers, for measuring soil moisture for developing fertigation strategies in glasshouse soils in The Netherlands. A fertigation model has been developed to apply water and fertiliser to soil-grown chrysanthemum


crops, without generating run-off or leaching to ground or surface waters. These new technologies present new opportunities for measuring moisture levels in growing media compared to tensiometers which became commercially available 45 years ago (Hansen and Pasian, 1999).

2.2 Review of Practices in Water and Nutrient Recirculation

Background to European irrigation systems

Currently in the UK there are limited numbers of recycling systems used in protected ornamentals, whereas for edible crops such as tomatoes and peppers recycling systems are extensive and based on rockwool. Those systems used in ornamentals consist of either ebb and flow on benches or floors, channel systems or containerised units. All protected pot plant producers in Denmark and most growers in Holland, Belgium and Germany use ebb and flow systems when ornamental crops are grown under protection. The area of recycling systems in Holland in 1989 are shown in Table 2.

Table 2 - Breakdown of different ornamental recycling systems in Holland (after Annevelink, 1999) as a % in pot plant nurseries (1989)

Production System % in size class (m2/nursery)<5000 5-10,000 710,000 Comparison

Ground 35 45 39 40Concrete floor 5 12 18 14Fixed bench 39 19 9 18Rolling bench 15 15 13 14Transport bench 2 5 18 11Unknown 4 4 3 3Total ha 182 252 483 917

The main methods of irrigation for containerised nursery stock and cut flowers in the UK is by overhead sprayline, whilst for pot plants and bedding plants, a combination of capillary matting plus seamless tubes are mostly used in the autumn. During the spring/summer overhead spraylines are widely used.

Ebb and flow systems give controlled application of water and therefore liquid feed and pesticides which are applied through the system, such as plant growth regulators and fungicides for controlling root pathogens.

Since the late 1960’s, Denmark, Holland and Germany have invested in systems of irrigation which allow measured water applications and therefore measured fertiliser and chemical application. In the 70's and 80's these systems became mobile and in the late 80's and early 90's they became mechanised, so that robots can now be used within the glasshouse to move plants around the system.

In the early 80's the governments of northern Europe within the EEC, introduced legislation which encouraged replacement of old structures and the incorporation of ebb and flow systems within the protected ornamentals sector. This initiative was to


avoid leachate pollution into the surrounding land and water. Experimental work at Aalsmeer and Naldwijk in Holland, Aarslev in Denmark and German research stations aimed to look at the specific problems occurring with the commercial uptake of these systems. A recent publication by Annevelink (1999) has indicated the most effective commercial use for a transport system within the glasshouse. The system requires the glasshouse structure to be developed around the system, which is developed to produce one to three crops. Continuing changes in pot or pack or crop reduces the system efficiency. The implementation of EU directives in the UK has been less dramatic, as described in Section 6.

Water Use

Cut Flowers

Research on restricted water application has been carried out on chrysanthemums and has been shown to delay production and lead to variable quality, thus affecting the economics of this crop. Where the majority of flower crops are still grown in the ground, guidelines on the amount of nutrient each crop requires have been approved by the relevant authorities (as described in Section 5). In Holland and Germany recycling systems have been employed for production of Gerbera and Roses with the use of rock-wool and coir slabs.

Containerised Plants

Recycling systems have most potential in the production of "containerised" crops such as pots, packs, etc. However, where the packs or pots are high in density, the container impedes water application from the ends of a bench or bed. Therefore irrigation can either be from above, or if the packs and pots are raised off the bench or floor level, from below, so that the water level can be raised and water can run freely beneath the containers and enter the container and substrate.

Recycling Systems

There are three main sub-irrigation recycling systems:

1. Concrete floors2. Transport tables3. Troughs or channels

Installation of such systems requires high initial capital expenditure. The expenditure will depend to a greater extent on the size of the nursery and the facilities into which that installation is to be placed. In many UK nurseries, such installations would be uneconomic due either to the configuration of the original structure, or the building itself making the layout so obtuse as to render the efficiencies in water application and labour less viable and probably uneconomic. The best systems are installed on nurseries of one hectare or above with a flow pattern for a particular crop or crops of a particular container size.

The most successful crops produced in the UK under such conditions are ‘All Year Round’ crops such as pot chrysanthemums and Begonia. Seasonal crops such as


Poinsettias, New Guinea Impatiens, Osteospermum and Gerbera can be grown successfully on these recycling systems. Changes in pot size may make certain crops more difficult to irrigate, particularly with small pots which may float away when dry unless held in tray containers.

The main problems with recycling systems are the need for the container, compost and the system to work in unison with the crop to avoid all mitigating factors which may affect quality or delay production time. These factors include compost and pots that seal the base and thus do not drain, or do not admit enough water. Root disease problems such as Pythium or Phytophthora can easily occur and spread in such a system. The local environment of the crop is changed by the ability to water and the ability to directly heat the floor or bench, thus compost temperature and moisture levels have become of greater importance. These factors can be maintained at 'optimum' for a crop whilst allowing the use of air temperature management to control plant height.

The main advantage of these systems is the control of water and fertiliser, reduction of pesticide loss and applying pesticides more accurately. In addition, these systems use a greater percentage of the floor area (up to 92%) when using ‘double-decking’ techniques or transport systems. Gers (1986) indicated two types of double decking, rotary and with tables. Rotary systems have now been superceded by tables which increase site use by up to 150%, thus allowing production peaks to be evened out.

In 1987 the Secretariat of the Dutch Horticultural Study (Anon, 1987) stated that "research must be a major concern for the ebb and flow committee". Research enabled modifications to be made to the microclimate in and around ebb and flow systems and monitoring whether the modifications affected growth, development and quality of plants. With trough or trough-like systems the air flow from below the trough was studied. Air currents and flows below the troughs were strongly influenced by the other air currents within the glasshouse, so it was difficult to achieve a uniform distribution of air between plants. Pot plants used in experiments included Schefflera, Ficus, Spathiphyllum and Guzmania. Research was requested on the control of Fusarium and Phytopthora within the system on cyclamen, Peperomia and Gloxinia respectively. At that time the Dutch researcher Rattink reported that no instances of spread of Phytopthora infection had been observed in the experimental ebb and flow cultures. This was because the prevailing systems provided good drainage and the spores were denied the time and opportunity to attach themselves to the roots in ebb and flow systems. The main priorities for the committee included research into the climate of ebb and flow concrete floor systems where dramatic decline in air humidity occurred in spring and summer.


Glasshouse design

Since 1987, the emphasis on glasshouse design has been based more on system requirements. Building glasshouses with extra height (4.5-5 metres) has helped to prevent poor air circulation in glasshouses where benches have reduced the height between the eaves and the top of the benches. Thus, although a recycling system has to be designed first and the house erected around it, improvements in house design are also incorporated.

Systems

Recycling systems (whether it be floor, bench or trough) require an even base on which the water can enter quickly, cover the whole area for ebb and flow systems and drain rapidly. For trough systems there is a different tube or channel for the water to enter at one end and flow away at the other, with container plants taking up the water as the water passes by. Water should remain on the surface of a system for as short a period as possible for water uptake, but generally no longer than 15-20 minutes.

The layout of any ebb and flow system will depend on the crop, the configuration of the land and the building structure. With bedding plants in packs, the system may need to have a facility to take the product outside on rails. This requires envelope doors at one end of the structure, normally the south end so that product can be "wheeled" out through the envelopes on the rails and tables. For pot plants, the actual configuration of the tables will depend on site, facility and cropping. The best site is going to be one of clean, level land. The system for transport tables can be static but is preferably mobile, when the product can be taken from the potting area, through the production system and return it to a harvest or storage area. Concrete floors must be laid out in a similar way, with road ways between them. On both table and floor systems, overhead cranes can be installed to move either product or tables.

With either system, plants grown in 9 cm or larger containers can be placed on the table or floor independently but with smaller plants, plugs, etc. plants will need to be contained in a tray. The plug trays should have ‘legs’. Benches can be double-decked either over the work area or amongst certain stages of crop production. The structure must have a minumum height of 5 m to the eaves.

Within the system it is possible, by optimising spacing, to increase plant numbers by up to 20%. This means that consecutive grading will give a better quality of plant at harvest.

Vegter (1988) indicated great support for concrete floors, despite the ergonomic drawbacks. He noted that concrete floors were developed for labour extensive crops with the use of robots for picking up and placing down. Benches are preferred for labour intensive crops.

Annevelink (1999) published tables which indicated the breakdown of different systems in Holland (see Table 2). Bakker (1988) indicated the criteria for floors: (these are listed in Appendix I) and stated that installation of below floor heating systems depended on the energy costs.


Heating

In each method of irrigation the heating system needs to be in place where it is most effective, i.e. with floors it should be built into the floor and each floor section temperature controlled. With benches, the heating system can be applied directly underneath and often as a separate system for the whole heating of the house. In some early trough designs the heating system was placed alongside each line of troughs. The bench type may prevent good heat distribution (e.g. if it has a plastic top rather than a metal top). If the tables are closed up to gain production within the house, the only penetration of heat will be through the base of the bench. Plastic bottoms to benches act as insulation, which may mean the benches do not dry rapidly nor does the required heat pass through to the compost in the container. With metal benches, i.e. aluminium, when heat demand is high, strips of drier areas of containers are likely to occur. Where bench edges are exposed the heat is likely to cause those plants and containers to dry more rapidly.

The LVG Wiesbden reported that cyclamen cultivated in channels achieved higher quality than was previously possible by conventional methods (i.e. capillary matting) (Harmer, 1990). Tensiometers fitted to automatic irrigation indicated different growing substrates can give better results (i.e. traditional compost with the addition of 10-20% aggregate material such as perlite, rice husk or coconut fibres gave better growth on crops such as the Gesneriaceae family).

High pot density will also cause extremes in microclimate in small areas. When the crop is pot-thick or at full canopy cover, the humidity and temperature within the crop are likely to be very high, 100% RH can occur in these cases. Once the crop is spaced the humidity levels will be lower until full canopy cover occurs. This dynamic and changing microclimate affects both plant pest and disease levels, as well as water use and therefore fertiliser application and nutrient uptake.

Water Quality

Water quality is of the highest importance in recycling systems as the same water will, with top-up water, be recycled continuously for several months. The water should be free of extraneous nutrients such as sodium, chloride and sulphates and have sufficiently low alkalinity. When water with high levels of alkalinity and salts is used, then fertiliser rates must be adjusted accordingly to meet the requirement of the crop at each particular growth stage. Where high levels of extraneous salt occur, the solution must be changed more often, otherwise plant growth will be impaired or delayed, with a consequent economic cost.

Media and Containers for recycling water systems

The container used for a recycling system needs to be designed so that the water can enter and drain from the container evenly and quickly. The container must be strong enough so that the holes at the bottom of the container allow drainage whilst also allowing water to be taken up. Too dense a substrate may reduce the quantity of water entering or exiting through the holes. A pot with only basal drainage can often cause a film of moisture which does not permit good entry or exit of water.


The substrate should be open but also moisture-retentive. Substrates which allow a build up of fine particles in the base of the pot should be avoided. When the crop is newly potted and has reached canopy cover, evaporation from the surface of the compost can be great and in such cases a build up of salt can occur in the top centimetre of compost. Additives to the compost such as bark, Perlite, coir or wood fibre can be used to improve the relevant media properties.

Nutrition

Nutrition in a recycling system requires the compost to be pH-adjusted to the requirements of that crop and then a fertiliser applied which is appropriate for the water supply and crop. Thereafter, continuous application of fertiliser can be applied according to EC and salt content of the water supply.

Economic Factors

These systems have been used for temperature modelling experiments at Aarslev in Denmark, in a three year programme starting in the winter of 1999/2000. Work has indicated that using controlled irrigation systems, a heat saving of 30% can be achieved, without affecting financial returns. Private enquiries have indicated that the 30% energy saving is being spent on increased lighting to raise the light levels on begonias from 30-40 W/m2 to 70 W/m2. On recycled systems this increases the winter quality of the product.

Water Use

Recycling systems can reduce water use by 30% or more over normal irrigation systems such as capillary matting and overhead application. The use of compost moisture measurement equipment has enabled further savings by applying water as the plants require it, rather than by computer clock, e.g. field-grown hydrangeas in Anger (Calopin, pers. comm.) and research by Hendriks (Hendriks, pers. comm.) on Poinsettias at Geisenheim indicated a saving of up to 25-30%. Research with the Frequency Domain (FD) monitoring equipment and the overall monitoring of water supply as plants require it has been carried out at Aalsmeer (Baas, pers. comm.).

Pest and Disease

The most common disease problems associated with recycling systems are Pythium, Phytophthora and Fusarium. Opportunist pathogens are likely to increase the incidence of these diseases if the system is poorly designed or if the compost or container are not of the quality required as previously discussed. Pythium and Phytophthora can be re-cycled around the system within the water. Large holding tanks allow Pythium and Phytophthora spores to sink to the bottom. Thinggaard and Middelbore (1989) reported high isolates of Pythium on Gerbera and regard control of Pythium and Phytophthora as important in plant health. According to Wohanka (1984) these problems could be reduced if compost and nutrition met the best specifications. Water sterilisation will also reduce pathogen levels in the system.

Summary


Recycling systems not only save water, fertiliser and pesticide but if set up properly and mechanised, they dramatically reduce labour input per unit of production. Savings in the production phase can be as high as 30%. By keeping the crop to the maximum density before spacing, the use of water, light and CO2 will also be optimised and this further increases crop throughput. Problems develop from using poor equipment within the system, (e.g. pot, substrate, etc.). The need for high water quality to maximise plant growth and reduce the disposal of water is important. Computerised management of the system enables accurate crop programming.


3. EVALUATION OF THE EFFICIENCY OF WATER AND FERTILISER USE IN DIFFERENT PRODUCTION SYSTEMS FOR PROTECTED CONTAINER ORNAMENTALS IN THE UK

The objectives of this project were to quantify water and fertiliser losses from different production systems by carrying out efficiency tests on a number of UK nurseries growing Poinsettias during the 1999 season. These tests involved single irrigation measurements as well as detailed monitoring of water use on a number of Poinsettia crops throughout the whole production period. Poinsettias were selected as a relatively standard crop grown on a range of systems over a long production period.

The experimental work was divided into two stages as follows:

3.1 Materials and Methods

Stage 1 - System Tests to Evaluate the Variation in Water and Fertiliser Use Between and Within Different Growing Systems on Commercial Nurseries

Identification of Nurseries and Systems

The primary objective of this stage was to establish the degree of variation of water loss between and within different growing systems. It was decided that, in order to reduce the number of variables affecting results, one crop should be selected. The crop selected was Poinsettia ‘Sonora’. This crop is widely grown across the UK using a range of different irrigation systems. By selecting one crop the research would be comparing like with like across the different systems, as crops would be at similar stages of growth and development throughout the country.

Seven irrigation systems were identified as being the most widely used systems for production of protected ornamentals. These were as follows:

‘Ebb and flow’ flood benching Overhead gantry (application usually to capillary matting) Hand-watering (using hosepipe) Capillary (various systems using capillary principles) Drip / trickle Overhead spraylines Trough track

It was not possible to identify growers producing a standard crop (i.e. Poinsettia) using all these systems. However, the following systems and nurseries were identified:-

Nursery System

Ebb A Ebb and flow flood benches 7m2 (recirculating). Flood for 4-8 minutes depending on crop demand.


Ebb B Ebb and flow flood benches 7m2 (recirculating). The bench is covered with thin capillary matting overlaid with perforated polythene. Flood for approximately 6 minutes depending on demand.

Ebb C Ebb and flow flood benches 10m2 (recirculating). Flood for 12-15 minutes.

Ebb/cap D Flooded capillary matting on benches (recirculating). Water is released onto one end of the bench and allowed to flood the bench. Capillary matting on the bench helps to retain some water after the flooded water has drained away.

Cap A1 Sand base on the ground overlaid with polythene, overlaid with capillary matting overlaid with perforated polythene. Trickle tape pipes (outlets every 20 cm) are used to apply irrigation at 9-15 minute sessions depending on crop demand.

Cap A2 Open mesh based benches (8.8 m2) covered with polystyrene overlaid with polythene overlaid with capillary matting overlaid with perforated polythene. Benches are on a slight gradient. Water is applied at the top of the bench (7-9 minutes) and allowed to drain down the bench through the matting.

Cap B1 Open mesh benches (20m2) covered with polystyrene overlaid with polythene overlaid with capillary matting overlaid with perforated polythene. Irrigation is applied by ‘spaghetti’ pipes feeding directly onto the bench at the base of plants. Irrigation is applied for approximately 30 minutes.

Cap B2 Sand base on the ground overlaid with perforated polythene overlaid with capillary matting overlaid with ‘Mypex’. Trickle tape pipes (outlets every 30 cm) are used to apply irrigation for 1-2 hour sessions depending on crop demand. This high volume acts as a ‘flooding’ system although excess water is not collected and drains into the ground.

Cap C Polythene covering on the ground overlaid with capillary matting. Irrigation is applied by a combination of trickle tape pipes and hand watering.

Cap D Plants individually placed in saucers with trickle pipe laid across the saucers. The saucers are spaced to coincide with the drip outlets on the trickle pipe.

Cap E Plants standing on open mesh benches overlaid with capillary matting (‘fleece’). Irrigation is applied by an overhead gantry with nozzles directed beneath the foliage to the matting.


Tric A1 Irrigation applied by pressure compensated drippers to each plant.

Tric A2 Irrigation applied by pressure compensated drippers to each plant (same as A1 but repeat test after some improvements had been made).

Tric B Irrigation applied by drippers to each plant.

Tric C Irrigation applied by drippers to each plant.

Trough A Plants spaced in troughs with a single pipe supplying water to each trough. Irrigation is on for approximately 11 minutes depending on crop demand. Unused irrigation water drains off the end of the trough onto concrete or bare soil below.

Hand A Sand base on the ground overlaid with ‘Mypex’ overlaid with capillary matting overlaid with perforated polythene. Irrigation is by hosepipe with lance.

Hand B Plants spaced on heated benches overlaid with polystyrene overlaid with polythene overlaid with capillary matting overlaid with perforated polythene. Irrigation is applied by a hosepipe with lance.

Hand C ‘Mypex’ over the ground. Irrigation applied by hosepipe.

Hand D Plants individually placed in saucers and watered by hand directly into the saucers.

Spray A Boom with spray nozzles was passed over the crop 8 times. Plants were standing on mesh benches overlaid with polythene, fleece and microperforated film.

In order to assess the comparative efficiency of each system the following test protocol was developed:

The Irrigation Test

All the selected nurseries (as described above) were visited during week 38 of the 1999 Poinsettia growing season. On each nursery a specified area of crop was irrigated. The area to be irrigated was measured and the exact number of plants and spacing was recorded. Twenty plants were randomly selected from the area and weighed using electronic scales accurate to the nearest gram. Weighed plants were labelled 1-20 and weights were recorded.


Following weighing the irrigation was applied as per standard nursery practice. The volume of water applied to the designated area was calculated. The method for this calculation varied depending on the system. On some systems (Ebb/cap D, Cap B1, Cap D, Cap E, Hand A, Hand B, Hand C, Hand D) it was possible to install a water meter (3/4 inch and 1 1/2 inch meters from LS Systems, Preston and LBS Horticulture, Colne). Different methods were employed in other systems where the fitting of a water meter was not practical. For example water was collected from drippers in drip trickle pipe systems and bench volumes were calculated in ebb and flow systems.

The twenty numbered plants were re-weighed 30 minutes after the irrigation had ended (or after water had drained from ebb and flow systems) and weights recorded. From this it was possible to calculate the quantity of water applied to each plant, the quantity taken up by each plant and therefore the quantity unused (most of which was assumed to be run-off).

The test was carried out once on each of the systems listed above during week 38. The plants irrigated were at a stage of dryness at which the nurseries involved would have irrigated (i.e. the tests were not carried out on plants that did not need irrigating).

Details of the production system were recorded as well as comments on crop quality, growing media type, spacing and pot size (all 1 litre volume pots). Notes were made on the fate of run-off from each system and any other relevant details which may affect the interpretation of results.

Growing Media

It is likely that the nature of the growing media used by each nursery will affect water uptake, leaching and water usage figures. To assess the effect of media the nature of the media was recorded on site. In addition, five plants from each nursery were selected randomly from the tested area. The foliage part of the plant was removed leaving the roots and growing media intact in the pot. These pots were then sent for laboratory analysis of Air Filled Porosity (AFP) and particle size.

AFP Method

In order to get an estimate of the physical structure the Air Filled Porosity (AFP) of peat or compost can be measured. This is a measure of the air space that remains after a compost has been immersed in water and completely wetted and then the excess water allowed to drain off under gravity. The method used complies with BS 4156. The method used for the determination of the AFP of the samples is that developed by Bragg and Chambers (1987) and adopted by the then government advisory service ADAS for the differentiation of mixes depending on their base ingredients. The methods and modification of it have been widely used and it is accepted that for mixes varying in more than 4% AFP , then the method can reliably be used for differentiation.

The pot (standard tapered plastic pot, height 12 cm, top diameter 13 cm, base diameter 9 cm) whose internal volume has been accurately determined (1150 ml) plus


compost is placed in a water bath and gradually wet from below, ensuring that the water level is sufficiently high to cover all the compost.

After initial wetting, the pot and compost are removed from the water bath and allowed to drain for 10 minutes. This completes one wetting and draining cycle; three wetting and draining cycles are carried out in total. The top of the pot is then covered with nylon gauze and secured by an elastic band.

The pot is placed on a ceramic tile in the water bath and saturated from below, adjusting the water level in the bath to that of the compost surface. When the compost is thoroughly wetted (water can be seen on the surface of the nylon gauze), the pot is slid off the tile onto a rubber (neoprene) sealing pad. This should be pressed firmly onto the pot base providing a water tight seal, and the pot transferred to a funnel on the drainage rack. The pad is then removed and the compost allowed to drain into a beaker for 30 minutes. The volume of drainage water is measured, and the AFP expressed in volume percentage terms.

Particle Size Analysis

Particle size analysis was determined as follows. On completion of the AFP test the samples were dried until approximately 20% moisture is retained. Each sample was then passed through a column of nine sieves (300 mm diameter) with mesh sizes of 13.2, 6.7, 4.75, 3.4, 2.0, 1.0, 0.5 and 0.1 mm. A pan was placed on the base to collect the finest particles.

The top of this column was covered with a lid and the sieves were shaken manually for approximately 15 minutes until a constant amount of peat was retained on each sieve. The sieves were then weighed and the amount of peat retained on each sieve was calculated. This figure was then converted to percentages of the total weight of the initial sample.

All the samples for the main monitoring sites were also sieved and in Appendix 20 the percentage of <2mm particles is plotted against AFP. The reason the less than 2mm particles were selected is that Scharpf (1997) attached high significance to increasing <2mm size particles and low AFP’s.

Water Quality and Composition of Run-off

Water samples were taken at each test nursery and analysed for nutrient content (using ADAS Hydroponic water analysis) at the ADAS Laboratories, Wolverhampton. Where possible samples were taken of:

Untreated water (i.e. borehole or mains water) Irrigation water (i.e. usually included liquid feed) Run-off

Costs of each System


Costings for a typical example of each of the seven initially identified systems was carried out. This is to include the cost of setting up and maintaining each system. Results can be seen in Section 4.2.

Stage 2 - Measurement of the Efficiency of Water and Fertiliser Use in Different Production Systems for Poinsettia throughout the Duration of the Crop

This stage extended the work in Stage 1 to enable the calculation of water and fertiliser use in four production systems throughout the production of a Poinsettia ‘Sonora’ crop from potting to sale. The four nurseries selected for this test were as follows.

Nursery System

A Ebb and flow flood benches 10m2 (recirculating). Flood for 12-15 minutes per irrigation.

B Flooded capillary matting on benches (recirculating). Water is released onto one end of the bench and allowed to flood the bench. Capillary matting on the bench helps to retain some water after the flooded water has drained away.

C Plants standing on open mesh benches overlaid with capillary matting (‘fleece’). Irrigation is applied by an overhead gantry with nozzles directed beneath the foliage to the matting.

D Plants spaced on heated benches overlaid with polystyrene overlaid with polythene overlaid with capillary matting overlaid with perforated polythene. Irrigation is applied by a hosepipe with lance.

Calculating Water Application

As with Stage 1, the water applied to a designated area of production was calculated. Water meters were used for nurseries B, C and D to record the volume of water applied through the season. Each nursery recorded the reading on the meter after each irrigation. The ebb and flow benching system in nursery A operated at a pressure greater than the water meter was designed for. On this nursery a designated staff member recorded the number of minutes that each flooding was on for and the date. At various times through the season the quantity of water applied to each bench was calculated by collecting the water applied in a measuring tank. For each nursery accurate figures were produced for water application through the season. It is important to note that nurseries A and B recirculate unused water and therefore it is not wasted or lost as run-off. However, other growers operate similar systems which are not recirculated.

Calculating Water Uptake by the Crop


To calculate crop uptake the irrigation tests (described for Stage 1) were repeated at fortnightly intervals from week 34 - 46. Twenty plants were numbered and weighed before and after irrigation during these tests (the same twenty plants each time). By calculating the mean water uptake across the irrigations through the season it is possible to get an estimate of the quantity of water taken up by the crop and the quantity unused or recirculated.

Calculating Fertiliser Application and Uptake

All participating nurseries applied fertiliser as liquid feed during irrigation. The quantity of fertiliser applied was calculated either by using the stock solution recipes and dilution factors, or, on systems making application by measurement of EC (i.e. nurseries A and B), by using the water analysis results for the irrigation applied. Total quantities of fertiliser (N, P and K) applied can be calculated for each of the nurseries.

Fertiliser uptake was calculated using laboratory testing at the ADAS Laboratories. At potting, 20 plugs from each nursery were analysed for fresh weight, dry weight, dry matter, calcium, magnesium, phosphorus, nitrogen and potassium. The whole plant was analysed, including the roots, but not the growing media. This figure quantified the nutrient content of the plants at the start of the work. This analysis was repeated on 10 plants from each nursery at the point of sale to give the nutrient content at the end of the production cycle.

Throughout the growing season the four nurseries participated in the ‘Poinsettia Monitoring Scheme’ operated by Bulrush Peat Company Ltd. This involved the submission of leaf samples to Natural Resource Management (NRM) Laboratories for analysis of tissue nutrient content. The results were used to compare nurseries participating in this research with other nurseries participating in the monitoring scheme, to ensure that those involved in this project were typical of industry standards.

Water Quality and Content

As with the tests in Stage 1, samples were taken of irrigation and run-off (where possible) water. This data can be used to assess nutrient losses and assess the potential environmental impact of the run-off.

The Growing Season

Different growers have different practices in terms of production techniques. Each of the four nurseries kept a ‘Crop Diary’ where any operations that affected the crop, (e.g. spacing, pesticide applications, changes in liquid feed) were recorded. Water application is also affected by light and temperature levels through the season. Light levels were recorded for each of the different locations to see how these relate to the water use results.

Growing Media


As with Stage 1 the growing media was analysed for AFP and particle size at the start and end of the growing season. Ten plants were analysed at both the start and end from each nursery using the methods as described in Stage 1.

Crop Quality

The quality of the crops produced on each nursery was assessed according to the protocol for project PC 156 (HDC funded Poinsettia variety trialling). This was carried out to ensure that water and fertiliser applications by each of the nurseries, was sufficient to ensure plants of acceptable quality.

Options for Run-off Management

Options for the collection and re-use of run-off were evaluated.


3.2 Results

Stage 1 - System Tests to Evaluate the Variation in Water and Fertiliser Use Between and Within Different Growing Systems on Commercial Nurseries

Irrigation Tests

Tests were carried out according to the method as described. Figure 1 shows the fate of water applied during the irrigation test in each system.

Figure 1 - Fate of water applied to each plant in the irrigation tests (1000 ml = 1 litre).

Full details of the results of the tests are shown in Appendix II. These results can be extrapolated to give an estimation of water use and loss through the whole season. Water uptake levels did vary between systems. To carry out this extrapolation the following method was used:

The total uptake per plant was assumed to be 5.5 litres through the season on each nursery. This figure was the average uptake figure recorded on the Stage 2 nursery tests.

This figure was then divided by the volume of water recorded to have been taken up during the irrigation test. The resulting figure gave the number of irrigations that would be required to supply each plant with 5.5 litres of water.

The figure for the number of irrigations required was then multiplied by the quantity of water applied at each irrigation (based on the irrigation test measurement). The resulting figure was the amount of water assumed to have been applied to the crop through the season.

5.5 litres was then subtracted from this figure to give the total water lost (or recirculated) through the season.

The following assumptions were made in making this extrapolation:

The total uptake for each plant on all nurseries was 5.5 litres through the season. The same amount of water was applied at every irrigation as was applied during

the irrigation test.


Plant uptake per irrigation was the same at each irrigation.

Clearly this would not always have been the case and the true values may vary from the extrapolated figures. This is highlighted by the way the figures for Ebb C (Nursery A in Stage 2), Ebb/cap D (B in Stage 2), Cap E (C in Stage 2) and Hand B (D in Stage 2) differ from the recorded values for Stage 2 tests (Figure 7). However, despite these limitations it was felt that the information showed clear enough trends to warrant inclusion in the report and provides a guide to the variation in water losses between different production systems. Figure 2 shows these extrapolations.

Figure 2 - Fate of water applied to each plant through the production season (1000 ml = 1 litre).

These figures highlight the potential use and wastage of large quantities of water in many production systems. For example, for every plant grown in Trough A nursery 41 litres of water could be lost from the system during the production season. For a nursery growing 10,000 Poinsettias on this system they should expect to be wasting 410,000 litres (410 m3) of water. The Cap B2 system would be losing 46.5 litres per plant which is equivalent to a loss of 465,000 litres (465 m3) water on 10,000 plants.

However, some systems were much more efficient in water use, particularly the trickle systems. System Tric A2 lost only 0.7 litres per plant through the season which is equivalent to a water loss of only 7000 litres (7 m3) if 10,000 plants were grown. A more detailed analysis of these differences is presented in Section 3.3.

Growing Media

Growing media was analysed at most (plants were not made available for this test on all nurseries) of the nurseries tested. Results of the analysis, for AFP and particle size, are shown in Appendix VI. AFP levels were generally low which reflected the quality of peat used during the 1999 season from the wet 1998 harvest. Results are summarised in Figure 3.


AFP for nurseries in Stage 1 tests

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Figure 3 - AFP results for nurseries in Stage 1 tests.

Water Quality

As stated in Section 3.1, water samples were taken of untreated water, water applied to the crop (i.e. including liquid feed) and run-off where possible. The results are shown in Appendices III to V and results for total nitrogen (nitrate-N) are shown in Table 3.

Table 3 - Nitrogen levels in analysed water during week 38

Nursery N mg/lUntreated Irrigation Run-off

Trough A 1.1 93.5 115.4Ebb A 1.6 38.3 no sampleEbb B 11.1 54.2 51.5Ebb C 12.2 101.3 91.9Cap A1 0.0 44.9 5.6Cap A2 0.0 no sample 5.6Cap B 0.7 40.3 69.2Cap C 1.8 46.3 29.6Ebb/cap D - borehole 8.1 64.3 61.1Ebb/cap D - mains 2.3 64.3 61.1Cap E no sample 11 no sampleTric A 1.1 25.2 no sampleTric B 0.0 85 no sampleTric C 0.0 38.7 no sampleHand A 2.3 25.5 23.7Hand B 5.0 121 149Hand C 2.3 51.2 85.1


Stage 2 - Measurement of the Efficiency of Water and Fertiliser Use in Different Production Systems for Poinsettia throughout the Duration of the Crop

Total Water Application

The quantities of water applied to the designated test area was calculated. This was then divided by the number of plants in the test area to give quantities of water applied to each plant through the growing season. Figure 5 shows the total water application to a single plant in the different systems. N. B. water applied in nurseries A and B was recirculated and therefore surplus water was not wasted.

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Figure 5 - Chart to show the quantity of water applied to each plant through the production season on the four nurseries A to D. Note that the figures are cumulative and not actual for each date.

Further details of water use through the season are shown in Appendix VI and VIII.

Water Uptake by the Crop

The irrigation tests were carried out on seven occasions through the growing season. Plants were weighed before and after each irrigation. The difference in weight represents the quantity of water taken up by the plant. The data collected in these tests is given in Appendix VII. As each nursery irrigated at different moisture levels, the uptake at each irrigation varied both between nurseries and between irrigations. Figure 6 shows the mean water uptake on each nursery at each irrigation. The error bars show the range (i.e. minimum and maximum) of mean uptake values.


A

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Figure 6 - Average water uptake by each plant per litre applied to the crop per irrigation cycle.

Lost Water

From an understanding of the water applied and the water taken up by the crops it is possible to calculate the quantity of water that is not taken up by the crop. Some of this water is lost through evaporation and some will be held for a time in capillary matting where this is used. However, the majority of unused water is lost as run-off. Water use and loss can be estimated for the whole production season for the 1999 Poinsettia crop. Total uptake of water per plant throughout the production season can be estimated by taking the mean uptake at each irrigation (Figure 6 above) multiplied by the number of irrigations. The fate of water applied throughout the season on different nurseries is shown in Figure 7.

Figure 7 - Fate of water applied to each plant in the tested systems throughout the production season (1000 ml = 1 litre).


Based on a mean cost of mains water of £0.67/m3 the cost of irrigating 10,000 plants would be approximately £66 for nursery A, £25 for nursery B, £51 for nursery C and £63 for nursery D. The cost for water application for nurseries A and B has taken the water uptake figures as a baseline. It is necessary to do this as the unused water is recirculated in these systems. The recirculating nursery B costs the least to run, in terms of water and fertiliser costs. The apparently high cost for nursery A is due to the high levels of water uptake by the crop on this nursery. Fertiliser Application and Uptake

Appendix XV shows the nutrient status of the crop before and after the tests as well as the quantities of fertiliser applied. Figure 8 shows the different levels of nitrogen application and loss from each system.

Nitrogen application and losses in each system

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Figure 8 - Quantities of nitrogen applied and lost from each of the systems tested.

There is no nitrogen loss from systems A and B as they are recirculating systems. However, unused nitrogen in nurseries C and D would have been lost from the system, largely in run-off. When these losses are calculated over a crop area then they can become considerable. For example, nursery D would have lost 11.3 kg of N for every 10,000 plants grown. If a proprietary feed mix had been used (e.g. 15-5-15) then this would require 57 kg of fertiliser which is equivalent to three bags (20 kg). Where fertiliser costs £1.00/kg then there is a direct loss of £57.00 for every 10,000 plants grown. Nursery D actually produced about 200,000 Poinsettias. Had all these plants been grown on the same system then 1140 kg of N would have been lost with a cost of £1140. Clearly there are financial reasons why growers should consider minimising water and fertiliser losses. This is discussed further in Section 3.3.

Nurseries A, B and C participated in the Bulrush Poinsettia Monitoring Scheme. Appendix XVI shows the results of the leaf tissue analysis. Leaf nitrogen content remained relatively consistent between the three (nursery D did not send in the correct samples and is therefore not included in the leaf tissue analysis) participating nurseries.


Water Quality

Water quality was analysed as described in Section 3.1. Full results of analysis are shown in Appendix X to XIII. Figures 9 and 10 show the levels of nitrogen ((NO 3 4.427) + (NH4 1.286)) present in the irrigation and run-off water at each test.

N content of irrigation and run-off water in nurseries A and B

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Figure 9 - Nitrogen content of irrigation and run-off water in nurseries A and B.

N content of irrigation and run-off water in nurseries C and D

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Figure 10 - Nitrogen content of irrigation and run-off water in nurseries C and D (Note that run-off samples were only collected from Nursery C in week 40).

These results show that the different nurseries have different approaches to liquid feeding. On systems where capillary matting is used, the N content of the run-off tends to be higher than the N content of the irrigation water. This is due to the fact that as nitrate is leached from pots it is held in the matting until the next irrigation when it is leached out as run-off. As water evaporates from matting it can leave the N behind leading to high N accumulations. Consultancy experience has shown that this high N can produce high conductivity levels (ECs) which can scorch roots. Nitrate is very prone to leaching. Levels of phosphorus (P) and potassium (K) in run-off were also high.


EC levels in the irrigation and run-off water are given in Appendices X to XIII and the levels are closely linked with nitrogen levels. The pH of water used varied between nurseries as well as between weeks on the different nurseries. The lowest pH’s were observed on nursery A where irrigation water dropped below pH 5.0 on two occasions. The highest pH of 7.8 was observed on one occasion on nursery C. The mean pH on the tested nurseries is shown in Appendix XVII.

Growing Media

Growing media from each nursery were analysed for AFP and particle size at the start and end of the season. Appendix XVIII shows the results of these analyses. The results show that the different media, all of them blended for Poinsettias, were fairly consistent in AFP and particle size. This enables results between nurseries to be compared accurately.

The results given in Appendix XVIII show that most of the AFP’s, on the nurseries tested, were in the 4-9% class, although nurseries A-D, showed an apparent improvement in the AFP’s over the assessment period.

Plant Quality

The test plants were scored for quality to assess their marketability. Results from the quality scoring are shown in Appendix XIX. The quality results were compared with typical supermarket specifications. All the plants assessed were considered to be of marketable quality which was typical of Poinsettia crops grown across the UK. However, all nurseries failed to meet height specification (see Appendix XIX). Plants on all nurseries were shorter than the ideal. However, some supermarkets did lower the height specification to 25 cm during the 1999 season, probably due to difficulties in finding crops of sufficient height. The plants at nurseries A and C had two weeks following the assessment to put on more height before the peak selling period.

Supermarkets specify a minimum of five breaks. The plants analysed in this test had approximately four heads but had sufficient secondary heads to meet the specification. The Poinsettias assessed did not represent the highest quality but were typical of UK production.


3.3 Discussion

3.3.1 Stage 1 - System Tests to Evaluate the Variation in Water and Fertiliser Use Between and Within Different Growing Systems on Commercial Nurseries

The tests were designed to assess the variation in water and fertiliser efficiency between a range of different production systems used for the production of protected ornamentals. Single irrigation tests were carried out on each nursery. This irrigation was timed around the week 38 production week for Poinsettias. Therefore all the Stage 1 irrigation tests were carried out when the crops in all the participating nurseries were at a similar growth stage. There are clearly limitations to carrying out such a test as a ‘one-off’ on so many different nurseries and for this reason the results should not be taken as absolutes but rather as a general guide. Crops would not have been at exactly the same growth stage and the moisture content of the growing media at the start of each test, may have varied a little between nurseries. However, data presented in Figure 1 showed that there are clear trends in water loss between the different categories of systems tested.

These Stage 1 tests proved to give key support to those carried out in Stage 2. In Stage 2, four nurseries were monitored through the whole production season for water use and loss. The Stage 1 results helped to demonstrate the variability both within and between production systems and in one case to highlight that the Stage 2 test for hand-watering (Nursery D and Hand B are the same system) was not necessarily typical of other hand-watering systems.

Each category of systems are considered below to assess their efficiency and potential for water saving:

Ebb and Flow

The main advantage of these systems is that the volume of water or fertiliser applied is not critical because the solution that is not used by the crop during an irrigation is recirculated to be available to other plants. The only losses that may arise would be from leaking benches or from emptying the recirculation tank. Tanks are emptied once or more through the season but very often the tank levels are allowed to run down first to minimise the quantity for disposal. In any case the quantity lost is likely to be considerably less than losses from open systems.

This system has been identified as the best for legislation compliance in countries such as Germany and The Netherlands. The practical advantages and disadvantages of the systems are described in greater detail in Section 2.2. The main reason why the system has not been adopted to any great extent in the UK is the capital investment cost in setting it up. These costs are given in Section 4.2 and show a typical cost of £33/m2 for an ebb and flow recirculating bench system.

The systems of greater concern are those ebb and flow flood systems that do not recirculate and just run-to-waste. In these cases, losses of water and fertiliser will be very high and if the data in Figure 2 is used as an example, then losses could be between 40 and 120 litres of water per plant per season. This level of loss is very high but not widely different from losses from Cap B2 and Trough A systems.


Capillary systems

Many irrigation systems for protected ornamentals rely to some degree on various types of capillary matting. The results from tests on capillary systems show wide variations, for example between Cap A1 and Cap B2. However, it is interesting to notice that the layout and construction of these two systems is largely the same with trickle tapes overlaying ‘Mypex’ or polythene overlaying capillary matting. The difference is in the management of the system. The grower in nursery Cap A1 irrigates ‘little and often’ whereas the grower in Cap B2 treats the system as an open form of flood flooring. In Cap A1 the irrigation is on for approximately nine minutes and in Cap B2 the irrigation is on for over an hour. This simply highlights that, if nursery Cap B2 had followed the practice of nursery A1, approximately 500 ml of water per plant could be saved at every irrigation. This saving would not only be in water but also in liquid feed, which is incorporated in most, if not every, irrigation.

The quality of the capillary matting used will influence its effectiveness. Old or poor quality matting tends to be of little benefit and will not store or distribute water very well. Good quality matting, on a level surface, can distribute small quantities of water well but is not able to absorb very large volumes, such as those applied in Cap B2. There is good potential for developing capillary matting systems for greatly reducing water losses without excessive expense. Growers should aim to adopt a system that makes full use of the matting properties and applies water evenly to the matting. It is proposed that different mattings and their properties are evaluated in a future study. Growers who rely on matting for irrigation must also be confident that the floor surface is level. Any undulation can lead to poor uniformity of water supply and for this reason many growers use matting as a buffer rather than as the sole irrigation method.

Trickle/drip systems

These systems, with drippers placed into each individual pot, are extremely efficient, with a loss as low as 20 ml per plant at each irrigation, compared with a loss of 54 ml per plant in the most efficient capillary system (Cap E). The only potential area for water loss is if the dripper has been pushed down to the pot base (so water drains straight out of the bottom) or if the media water holding capacity has been reached. Losses can also occur if not all the drippers are placed in the pots but on the whole water loss is very low. The results in Tric A1 showed some inefficiency and this was found to be due to some drippers being at the base of the pot, which was then corrected. When the test was repeated the average water loss from each plant at each irrigation was reduced from 95 to 20 ml. The other advantage of drip systems is that they optimise chemical and fertiliser use.

The main disadvantage with trickle irrigation is the initial cost and labour requirements to insert the drippers. The system is not suitable if growers need to space the crops a number of times unless long drip leads are used. Nursery Tric C set up their drip system with plants at a very wide spacing (4/m2 compared to the typical 10/m2) from the start of production, then installed the drips and did not space them again. This is practical where the space is available but most nurseries need to space plants to maximise the use of available area. Drip systems used with water high in


bicarbonates are liable to furring up with calcium deposits and acid dosing should be incorporated in the irrigation system.

Trough track

Water loss levels in this system are very similar to those for recirculation in the ebb and flow systems. This system showed that almost 1.5 litres of the water applied to each plant at each irrigation was lost and drained off the end of the troughs into the ground. Trough track offers the potential for efficient water use but only when it is a part of a recirculating system. The cost of the water lost by the nursery using this system was not significant as water was taken from a borehole. However, such systems are very wasteful particularly as fertiliser is incorporated in all the lost water.

Hand-watering

These nurseries water using a hosepipe. This method is labour-intensive and potentially very wasteful, with losses up to 613 ml per plant in one irrigation (Figure 1). Hand-watering with a lance on Poinsettias can also damage the plants if not done with care. Nursery Hand B is the same as Nursery D in Stage 2; the reasons for the different results from this nursery are explained later in this section.

Spraylines

Spraylines are not widely used for Poinsettia production and therefore the test for this system was specifically set up for the project. It was considered that spraylines should be tested as they represent a significant number of the irrigation systems used under protection particularly for bedding crops. The sprayline system wasted 159 ml water per plant. This inefficiency was not surprising but it is interesting to note that losses were not very different from most of the capillary systems.

Water Quality

The importance of good water quality is described later in this section. Nitrogen (N) levels are a good indication of nutrient levels in the water. These were shown in Table 3. It is interesting to notice that some nurseries start off with water containing N, e.g. nursery Ebb C had 12.2 mg/l N in the water used from the borehole. Once feed is added this makes N levels in the irrigation water very high. It is wise for growers to regularly analyse the water used as such high levels of nutrients in untreated water should be accounted for when adding feed. The high levels of N in run-off water highlights how easily N is leached from containers. In some cases the N level in the run-off was higher than the level applied in the irrigation water. This tends to occur where capillary matting is used. Water (including feed) is stored in matting but some of the water will be evaporated from the matting during hot weather, leaving a concentration of N in the matting. This has become a problem on some nurseries where EC levels of the matting have reached such high levels that crop roots have been scorched.

Growers should be aware that run-off water contains as many, if not more, nutrients than the feed mix applied to the crop. In most cases the run-off exceeds the 11.3 mg/l N limit set by the EC Drinking Water Directive. Growers found to be allowing this


run-off, at this N concentration, to enter watercourses could face legal action if discovered.

3.3.2 Stage 2 - Measurement of the Efficiency of Water and Fertiliser Use in Different Production Systems for Poinsettia throughout the Duration of the Crop

Total water application

Figure 5 shows the water application trend for each nursery in Stage 2. More detail is shown on the graphs in Appendix VIII. The highest water applications to the crops were, not surprisingly, in nurseries A and B. Both these systems are recirculating and based on flooding. Nursery B uses capillary matting, in addition to the flooding to prolong retention, and this is reflected by the lower volumes of water applied. The systems tested in nurseries C and D are not recirculating and therefore water not used by the crop is lost. N.B. not all ‘lost’ water is run-off. Some will be evaporated and some will be held in the matting for a while before taken up by the crop.

The charts in Appendix VIII show the different watering strategies adopted by each nursery. The ebb and flow flood bench system in nursery A applied set quantities of water at each irrigation. This was adjusted once as the season progressed, by increasing the length of flooding time. The earliest part of the season represents a period when the crop was hand watered. Although nursery B also floods based on a set number of minutes, the actual quantities applied varied between irrigations. This may have been due to variations in water pressure, as the water meter installed on the system accurately recorded water application. Irrigation was applied fairly consistently during September and the early part of October and after this smaller amounts were applied due to prevailing weather conditions. Appendix IX shows that light levels in nursery B were lower from the second week in October, so reducing evapotranspiration and crop demand for water.

Nursery C applied a ‘little and often’ approach through the season until the second week in October, when application increased significantly. This coincided with high light levels as shown in Appendix IX, and followed a period when water had not been applied. The most likely explanation is that the plants were dry and needed extra water to return compost moisture to the correct level. Water was not applied during the last part of October and again this coincided with a period of low light levels and cooler weather. The increase in water application in November also reflected weather conditions in addition to the growth stage of the crop nearing sale.

Water application in nursery D adopted the ‘little and often’ principle to a greater degree. For much of the season the crop was watered nearly every day, although in many cases this was spot treatments of dry areas. The higher water applications in early October coincided with high light levels as well as following a period when the crop had not been watered. There was some concern that the quantities of water applied in the system seemed remarkably low compared to the results from other hand-watering systems as described earlier. On further investigation, it was found that although the crop is hand watered, the water applied to the bench did not really drain from the bench but was trapped by the polythene overlaying the benches. The polythene was curled up at the sides of the benches and acted almost as a flood bench. Plants take up virtually all the water applied as they sit on the bench. Without careful


monitoring of crop condition, this system could be risky in terms of crop quality, as overwatering could very easily occur. For this reason, this system may not be typical of hand-watering systems where unused water drains as run-off. This result highlights the value of the Stage 1 tests, the data from which can be used to assess typical water losses from hand-watering systems.

Water Uptake by the Crop

The quantity of water taken up by a plant in a container at any one irrigation will depend on a number of factors. These include:

Quantity of water reaching the pot. Initial moisture level (saturation) of the growing media. Water holding capacity of the media.

The degree of wetness in the container before and after irrigation depends largely on the watering ethos of the nursery. Some nurseries are notably ‘wet’ whereas others are ‘dry’. The ethos adopted will depend on what the individual grower feels is best for the crop, labour requirement for each irrigation and the overall cost of each irrigation operation. In some ways it would have been useful to ensure that irrigation only took place when the crops on all the nurseries in this study reached a set level of dryness. This could have been measured by use of soil moisture probes similar to those discussed in Section 2.1. However, in reality it would have been unrealistic for participating nurseries to irrigate based solely on soil moisture measurements without past experience with the technique. In addition, use of soil moisture probes would not have been an accurate reflection of actual commercial practice.

Figure 6 showed the variation in mean water uptake in each of the different nurseries along with error bars to show the range in different irrigation tests. The lowest levels of water uptake were in nursery B and the highest in nursery D. The uptakes for each nursery can be explained by the irrigation system and approach used.

The lowest uptake on nursery B can be explained by the reliance on capillary matting in this system. Matting is flooded at each irrigation and the plants take up water over the following hours. The tested plants were weighed approximately 30 minutes after each irrigation but by this time the crop may not have taken up all the water available from the capillary matting. If the plants had been weighed a few hours later, the weights may have been greater. However, after additional time other factors would affect water volume, such as evapotranspiration which would reduce the water volume in the container. Thirty minutes after irrigation was an acceptable compromise but this may explain why uptake seemed lowest in this system.

Uptake in nursery A was slightly higher and this was probably due to the higher flooding levels and the fact that the system does not rely on capillary matting. The uptake levels were not as high as nurseries C and D as nursery A tended to keep plants in a wetter condition and irrigated more frequently.

The highest uptake was observed in nursery D. This is to be expected as the water applied remains on the bench surface until it is taken up by the crop. The plants were drier before irrigation than other nurseries due to the use of high heating temperatures


under the bench. Nursery C was intermediate between nurseries B and D as the system is a combination of capillary and flooding which holds water on the benches for shorter periods.

Analysis of variance was used to compare weights before and after irrigation and any differences between the seven irrigation tests. This analysis showed that there was nearly always a significant difference between the different nursery sites in terms of plant weights before and after irrigation (see Figure 6). The weights of tests plants were more variable in nurseries A and D in the first two tests than later in the season. This is simply explained by the fact that both nurseries relied on hand watering for this test phase. Therefore saturation levels between pots would have been variable until plants had established in time for the later tests.

The final analysis combined the data for each site and showed that the differences between sites were consistent over time. Nursery C usually had the lowest weights after irrigation and the smallest difference in weights. The biggest weight differences were seen on Nursery D, where hand-watering was used, as discussed above.

The mean water uptake data for each nursery were used to calculate the total water uptake through the season as shown in Figure 7. Total water uptake varied between nurseries: The highest water uptake seemed to be in nursery A where each plant took up

approximately 10 litres of water through the season. Water uptake was nearer to 4 litres in nurseries B and C but as stated above it

should be remembered that these systems rely on capillary matting and water uptake may extend beyond the period after the final weighing.

Nurseries A and D represent systems where water uptake is fast and therefore it has been possible to record the full uptake values.

A margin of error (of a few litres per plant) should be accepted for nurseries B and C. However, this does not change the overall trends shown by the results when calculating water losses.

Water Loss

Other than losses from leaking benches, the occasional emptying of water tanks and evaporation, there are no losses from the flooding systems in nurseries A and B. Unused water is recirculated and the advantages and disadvantages of the systems were described earlier. The water losses from nursery D seem remarkably low compared to the hand-watering systems. The Stage 1 results clearly highlighted that this system was not typical of hand-watering systems. Nursery D is an interesting example of how systems that are relatively cheap to set up can be efficient in water use.

The watering system tested in nursery D is described in Section 3.1. It was not easy for the water to run-off from the bench and most is kept on the bench. Thus the system is a ‘semi-flooding’ system which clearly uses water very efficiently. With careful management, Poinsettias can be successfully grown under this system. Section 3.2 shows that the crop was of marketable quality. However, there are drawbacks. The crop would need to be managed very carefully; this nursery had one individual responsible for the irrigation, who did not over-water the crop. When


water is trapped on a bench, in this way, there is a danger that the media could become saturated and promote disease spread. This particular crop did not suffer from these problems; it was carefully managed and also the benches were heated, so excess water would soon have been evaporated. Another drawback is the labour requirement in a system like this. Section 4.2 shows that labour costs for glasshouse hand-watering can be £4,680 per year. These needs to be compared with the costs of installing a mechanised closed system.

The cost of water loss is referred to in Section 4.1. Water costs would be highest in nursery A if mains water was used with a cost of 4 pence per plant. This would cost £400 to irrigate 10,000 plants for a season. However, water costs are not high when considered in this way. The cost of fertiliser is more significant.

Fertiliser Application and Loss

Quantities of fertiliser used and lost from each system are shown in detail in Appendix XV. The quantity of fertiliser applied and taken up are based on the quantities of water applied and taken up. N is a good indicator and the element of most concern from the point of view of run-off. Figure 8 shows that the actual plant uptake of N in the different systems varies from 0.54 g per plant at nursery C to 0.91 g per plant at nursery B. However, compared to the figures for unused N, these figures are quite consistent between nurseries. The highest loss of N was at nursery D where for every plant 1 g of N was lost through the season. The example given in Section 3.2 showed that this could be equivalent to 11.3 Kg of N per 10,000 plants grown.

If a number of assumptions are made this information can be used to estimate fertiliser losses from the systems in Stage 1 tests. The assumptions are as follows:

10,000 plants are grown Grower uses a proprietary feed mix containing an NPK ratio of 15:5:15 Stock solution is 1 kg fertiliser in 10 litres water Stock solution is diluted to 1 in 100 giving 1 kg of fertiliser in 1,000 litres of

irrigation water and 1.0 g of N in 1 litre of irrigation water Fertiliser costs £1.00 per kg Feed is applied in every watering Water uptake on each system is 6 litres per plant N levels in run-off are the same as in the water applied (Appendix V shows this is

a fair assumption)

The estimated fertiliser losses are shown in Figure 11.


Estimated cost and quantity of fertiliser loss from 10,000 plants in Stage 1 systems

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Figure 11 - Estimated cost and quantity of fertiliser loss from 10,000 plants grown in Stage 1 systems through the production season.

Clearly many of these assumptions will not apply to all nurseries but the figure shows an example of the losses of fertiliser and the value of those losses. It is alarming to calculate that Nursery Cap B2, if it was growing 100,000 Poinsettias on this system, could be losing 4.6 tonnes of fertiliser with a value of £4,650. With Poinsettias spaced at 10/m2 then this is equivalent to £4,650 / ha.

Data such as this helps to highlight the potential inefficiencies of some production systems. However, the data also shows how systems that are not necessarily ‘closed’, can be made to be efficient. For example the losses from nursery Cap A1 were only 15% of the losses from Cap B2. These two systems are similar but the different approach to watering gives this huge variation in results.

Appendix XV also shows that losses of K and P were high and in some cases losses of K were considerably higher than N losses. Fertiliser can be saved by applying different mixes (according to crop requirements) through the season but the greatest savings will be obtained by improving application efficiency.

Growing Media

All the samples had more than 20% <2mm particles and it can be argued that this high proportion would certainly reduce the AFP values. However, the materials selected for the 1999 growing season will nearly all have come from the 1998 peat harvest which was, for all suppliers in Europe and the Baltic, very poor quality. The harvest conditions and the peat in store were wet. This led to very fragile structures of peat being produced which, when dried, easily broke down.

The dry sieving method used in the assessments was originally developed for soils, and relies on the aggregates remaining stable at the various particle sizes in order to give a true picture of the particle size distribution. In this case the drying of the peats, which were already fragile in their wet state, probably inflated the percentage of particles less than 2mm. Arguably this would occur anyway as the material is screened, bagged, tipped, put through potting machines and watered. Even where


attempts are made to reduce the <2mm particle content of the materials in a bad year they cannot be realistically removed. Additionally, where additives such as bark and perlite are added they are not pre-screened to remove excess levels of <2mm and they can even lead to a greater overall percentage of this fraction.

The most important message from this data is that these type of determinations should be made more regularly with substrates. This will allow the management strategy on the nursery to be adjusted to optimise the nature of the substrate. In years where the substrates, from whichever source, do contain 20-30% <2mm particles and the AFP’s are low, then the water management has to be very careful to avoid excess wetness, particularly in the base of pots.

The Importance of Water Quality

Potable Water Supplies

Many nurseries in the UK use mains water as it is regarded as being of the highest quality. Certainly any public mains supply in the UK is of the highest quality with regard to its 'potable nature', i.e. the indication that it is fit for human consumption. Water companies must meet standards for the potable water supplied. However, whilst the water in the mains may be fit for drinking, its fitness for use on ornamental crops may be significantly different. For example, the human detection point for chloride in water is 250 ppm and the upper threshold for action by water companies is 450 ppm chloride, but it is recognised in horticulture that levels of chloride above 80 ppm may cause severe restriction in plant growth.

Rainwater

The purest natural water is rainwater before it reaches the ground, assuming that there are low levels of atmospheric contaminants such as sulphur dioxide and nitrous oxide. Even if these two oxides are present the rainwater will still be relatively ‘clean’ in chemical terms. Once the water touches a surface then the nature and properties of that surface will determine the subsequent quality of the water.

If the rainfall falls on hard impervious rocks, such as those in the Scottish highlands and English Lake District, then the water collected in the surface reservoirs will be devoid of many additional minerals with the exception of aluminium and silica. The exception to the rule is where the slightly acidic rainwater in these areas first passes through the upper organic 'peaty' soil layers, absorbing organic complexes (fulvic and humic acids) and then passes through heavy metal veins such as those consisting of zinc, copper and arsenic. This can result in an organic complex of such mineral deposits which can eventually reach reservoirs. This problem was recognised in the very early days of mains water supplied from such areas. Methods of 'flocculation' of the organic colloids have become established practice to both clarify the water and remove the metals.

The resultant mains water from such sources has little or no dissolved carbonates other than those applied at the treatment works to avoid corrosive action on metal pipes in the system. This was introduced once it was realised that soft slightly acidic


water was continuously dissolving lead supply pipes and hence giving human health problems. This type of water, if supplied in public mains, is the purest and softest water and is the easiest to deal with for both fertiliser inputs and effectiveness for avoidance of problems such as algal growth.

At the other extreme of the spectrum is the rainwater which initially falls on chalky soils overlying chalk rock. In this case the slight acidity of the rainwater starts the process of dissolving carbonated minerals in the profile, to the extent that the water entering a chalk aquifer is saturated, both in elements such as calcium and magnesium and also carbonates in the form of bicarbonates, which give rise to temporary hardness of the water. Water on the south coast and the London basin, where the boreholes for public supplies are direct into the chalk aquifers, can carry the maximum possible levels of temporary hardness. This is usually expressed as the alkalinity of water and can be 350 ppm or more. This water is in reality a saturated limewash solution and will cause rapid increases in the pH of substrates over a few weeks of use. The smaller the container, the faster the rise in pH. This rise in pH will then have the associated problems of nutrients being increasingly limited in their availability to the plant. There will also be a greater tendency for algal growth and deposits both on leaves and from drippers and overhead spray nozzles.

In between the extremes of the very soft and the extremely hard waters there are many variations. In addition, local geology may influence the water quality in other ways. For example, water taken in areas around the Winsford area of Cheshire, the Newport area of Shropshire, the Droitwich area of Worcestershire, or the Windsor area of Berkshire may come from boreholes that have very high levels of sodium chlorides. This is because each of these areas sits over naturally occurring deposits of rock salts. Similarly, water in parts of Nottinghamshire taken from marine coal bands may also have high chloride and sulphate levels. Additionally, in some coastal areas the saline head of water may have exceeded the fresh water head so much that boreholes have in fact turned saline. Examples of this are to be found in the Pilling area of Lancashire and the Essex coastal areas.

Chlorides

Chlorides, as a hazard in water supplies, have long been recognised in some sectors of agriculture. An ADAS report on water quality in the eastern region (Anon, 1970) for the dairy industry considered the water in terms of the chemical quality of farm water supplies on a parish by parish basis. Many of the samples indicated extraordinarily high levels of chloride. Ranges from 30 ppm, which is a typical background level, to 1200 ppm were found. Even within some specific parishes, different sampled boreholes gave readings which were at least a factor of two to three times different.

Nitrates

In more recent times, from the early 1980’s onwards, considerable attention has been paid to nitrate levels in drinking water and the association of high nitrate levels with ’Blue Baby syndrome’ (Briercliffe, 1998. HDC PC 59a). At present the World Health Organisation (WHO) recommendations for water fit for drinking to restrict the nitrate content to 50 ppm nitrate or 11.1 ppm N. Studies in this project, around the UK indicate that background levels of nitrate N can be far in excess of WHO


recommendations. In some cases nitrate N can reach levels at which the ‘raw’ water for many crops is in fact a dilute feed.

Iron

Finally, the iron content of many borehole waters may give rise to problems both in terms of precipitation, in the form of orange ochrous slimes and also the deposit on leaves of a film of oxides. Many boreholes carry iron in a reduced state, such that it is mobile. However, on exposure to air the oxygen rapidly converts the reduced iron to an oxide which then causes the problems described. In the USA, systems exist for the removal of the iron after oxidation with strong oxidising agents such as permanganese. This is currently being investigated in the UK for commercial development.

3.4 Options for Improving Efficiency

3.4.1 Improving Existing Systems

Growers wanting to completely eliminate run-off will have to look seriously at recirculating closed production systems as specified and costed in Section 4.2. Comments on the viability of installing new systems are discussed in Section 3.4 below. However, many growers will not wish to invest in new production systems. After all the factors are taken into consideration it may be more realistic to maintain existing systems but improve the efficiency. Section 8 of HDC project PC 59a (Briercliffe, 1998) outlines some key options for minimising run-off. In addition to the suggestions below, this also suggests paying careful attention to media selection. This will involve a compromise; on the one hand growers want an open media but on the other such media can promote nutrient leaching. Wetting agents can be incorporated (as they are in most proprietary media mixes) to alleviate some water losses. This section considers how efficiency can be improved in each of the systems tested in this research.

Ebb and flow and trough track systems

Little can be done to improve the efficiency of these systems if they are recirculating already. The main concern is to ensure that these systems are recirculating. Trough A system is an example of such a system that does not recirculate and there are some growers using ebb and flow benches that run-to-waste. In these cases the volumes of water, that are recirculated, will be lost as run-off (see Figure 7).

Water losses can occur in a recirculating system, particularly when the recirculating tank is emptied. Good practice for these occasions would be to let the tank run as low as possible before emptying it. Water can also be lost by evaporation directly from the bench or floor, particularly if the flooding process lasts a long time. Research by Otten et al. (1999) cited in Section 2 showed that most water applied to flood benches is absorbed within the first five minutes and therefore frequent applications of small quantities will result in more efficient water use. The increased frequency of irrigation on these systems rarely results in increased labour, as such systems are largely mechanised already.


Capillary systems

The wide range in water losses from capillary systems was shown in Figure 1. The key method for improving efficiency in these systems is to adopt a ‘little and often approach’. Efficient capillary systems will have the following characteristics:

Good quality capillary matting which has not deteriorated with overuse. Matting placed onto a level surface. Matting should have a solid film underneath (e.g. polythene) to prevent leaching

through to the ground beneath. Matting can be overlaid with perforated polythene to increase its lifespan and

reduce moss and liverwort contamination. Water can be applied by drip/trickle tapes or emitters but water release on the

matting should be balanced across the mat area to avoid concentrated pockets. Water should be applied ‘little and often’ enough to wet the matting without

producing run-off; where beds are not level then more water will need to be applied. The length of time recommended for each nursery will vary depending on matting, system and water pressure.

There are a number of capillary matting products available to growers but there is little independent data to show which are the best to use. Further work is needed to assess the different options available to growers and for developing the most efficient capillary system. In the mean time growers should experiment with different high quality mattings as quality varies considerably.

Drip systems

The research showed that drip systems were very efficient and they only cost another 70 pence/m2 to install compared with a capillary system (see Section 4.2). The main drawback is the labour required in inserting and maintaining drip nozzles. The system works well on pots that are large enough (i.e. 1 litre or above) but are not practical for smaller pots or packs and trays. Even with drips in large enough pots there can be problems when it comes to spacing and crop handling. Drippers need regular checking to ensure they are emitting water in the right place and are not blocked. The nurseries tested in Stage 1 tests, that use a drip system, find it very effective and they would not change to a different system. The dry aerial environment also helps to prevent disease spread.

Hand-watering

These systems are notoriously inefficient and labour intensive. Although they are the cheapest systems to install they are the most expensive to run (see Section 4.2) and with the problems of crop damage, poor uniformity and a shortage of horticultural labour, many growers are turning to alternative options.

The efficiency of any hand-watering system depends largely on the individuals who do the job and how well they are aware of crop demand and when they reach the point that they are applying too much. The nature of the Poinsettia crop means that, to avoid foliage damage, any watering lance has to be directed to the pot underneath the foliage and hence much of what is applied is lost onto the floor. The use of


polythene and capillary matting under the crop will help to retain some of the water lost and growing crops on benches will give greater control and reduce potential physical damage.

Nursery D is an example of an efficient hand-watering system but, as with most efficient systems, it also relies on capillary action to some degree. Simply using a shut-off valve on the lance is another way to ensure water is not wasted when the crop is not directly being watered.

Spraylines

Work by Hall et al. (1998) showed that overhead sprinklers lost between 55 and 79% of the water applied. This agrees with the results in this project, which showed that the sprayline system evaluated was on the more efficient side of these values. The sprayline system tested was attached to a boom and was therefore probably more efficient than many attached to roof lines. These systems are heavily relied on for the production of protected ornamentals but are only about 50 pence/m2 cheaper to install than a capillary system. The overhead spray is not only inaccurate and wasteful but also promotes an environment suitable for the spread of disease pathogens and algae.

The efficiency of these systems can be improved to some extent by improving the layout of nozzles and choosing the best type of nozzles. The system should be designed so that the spray irrigates the beds containing crops rather than the paths. Irrigation should be applied during dull periods when high temperatures will not lead to high evaporation rates. Nozzles at the ends of rows should have 180o angles. Beyond these simple steps there is little potential for water saving in these systems under protection.

Gantry systems

These systems provide a more targeted water application and in production of packs of plants these can be very efficient. Water is not lost to paths and carefully targeted nozzles ensure good uniformity of water application. Efficiency can be improved by shutting off nozzles in sections where plants are not present and applying water during dull periods to minimise evaporation. As with spraylines, gantry systems are not used to any extent in the UK for the production of Poinsettias and therefore could not be included in directly comparative work.

Minimising fertiliser losses

The research in this project has shown that fertiliser losses can be very high. Most nurseries feed Poinsettia crops at virtually every watering. It is better to do this than apply large quantities all at once but application should still be based on an understanding of both crop requirements and the nutrient status of the growing media. Media should be regularly analysed and fertiliser application should be adjusted to meet the requirements of the crop as the National Poinsettia Monitoring Scheme aims to do. This practice could potentially save considerable quantities of fertiliser as well as improving crop quality.

3.4.2 Investing in new systems


Few UK nurseries are investing in fully recirculating systems. Primarily this is due to the high cost of ebb and flow flood systems (£28.60-£33.29/m2) in the initial installation. However, when considering such systems a long term view needs to be taken and all aspects considered. Horticulture is facing a crisis in terms of labour shortages. The systems that are cheapest to install are also those with the highest labour requirement. The annual labour costs for a hand-watering system in Section 4.2 were estimated at £4,680 compared with £1,196 in an ebb and flow floor system. This may still mean a long-term pay back, but as pressures on labour and water increase so these should be considered as serious options.

The irrigation system frequently takes a position of low priority in nursery planning but any new developments on a nursery should carefully consider this aspect. However, ebb and flow flood systems are not the only option recommended here. Manufacturers are increasing the number of products on the market available to growers. One example is the ‘Bottom-Up’ system from Australia (supplied by LBS Horticulture). This system consists of a sealed matting with pipes feeding water onto the matting. The principle behind it is the same as ebb and flow systems but the cost is lower. The suppliers claim a minimum water saving of 60% compared to overhead systems but as with most capillary systems it is important to have a level surface. The cost for these systems varies depending on the width purchased but an example is the 1.5 m width which costs £25.24 for the first metre (including cost of a pressure regulator) and then £6.60 for each extra metre (summer 2000 prices). This still makes the system fairly expensive compared to other capillary systems which can cost £2-3/m2 to install.

Growers installing new systems should take care to ensure that the aspects discussed in Section 3.4.1 are taken on board.

3.4.3 Collecting and Recirculating Irrigation Water

The collection and re-use of run-off water is an obvious way of reducing water losses and increasing the efficiency of water use. However, in practice this can require extensive construction work. Systems, such as ebb and flow are often designed to collect and recirculate run-off water but most other systems are not designed with this in mind. The feasibility of setting up such a system will vary from nursery to nursery. Some can make use of natural slopes or previously installed drainage systems, whereas others will require more work.

Once space has been found for storing collected water the next main problem is how to overcome the threat of disease. Run-off water will often have been in contact with plant material as well as moving across the ground and other surfaces. These all contribute to the likelihood of picking up disease pathogens in the water. The different options for preventing disease spread and the treatment methods available are outlined in Section 4.3. The costs listed in that section need to be weighed up against the costs of installing more efficient irrigation systems or simply modifying existing practice to improve efficiency as described in Section 3.4.1.

Reed beds provide another alternative for water treatment. Reed bed systems work on the principle of an artificial wetland. They rely on the flow of water through


gravel or soil in which reeds are growing. The key features are as follows (Lightfoot-Brown, 1999):

The rhizomes of the plants open up the substrate to provide a hydraulic pathway The waste water is ‘cleaned’ through aerobic and anaerobic bacterial activity

which breaks down chemical residues and removes pathogens The chemical load of the water is further reduced through uptake of minerals by

the root systems

The most commonly used plants in such systems include Phragmites australis, Typha latifolia, Iris pseudoacorus and Scirpus lacustris. Various reed bed designs can be adopted to collect nursery run-off and feed it through the reed beds. One of the key drawbacks with this system is the large area that the beds occupy. The larger beds are the most effective and nurseries need to have considerable space for setting up such systems. Reed beds are known to be effective at removing suspended solids, nitrogen, phosphorus and heavy metals but they are relatively unproven in respect of plant pathogen removal. As with slow sand filtration a reed bed develops a microbial ecosystem which is likely to be antagonistic to plant pathogens but further work is required to assess how effective and reliable this is.


4. WATER, IRRIGATION AND WATER TREATMENT COSTINGS

4.1 Water Costs

UK growers use water from the following main sources: boreholes, wells, surface water abstraction, rain water collection, recycling and the mains. Water abstraction from boreholes, wells and surface waters requires a licence which can be obtained from the Environment Agency and once the system is operating the water costs are relatively low. However, many growers still rely on mains water supplies, which incurs a significant production cost. The cost of water varies throughout the UK. Some examples of this range in prices are shown in Table 4.

Table 4 - Water Company prices paid by nurseries in 1998 (Anon, 1998).

Water Company Price paid £ per m3

Mid-Kent 0.68Three Valleys 0.58Cambridge Water 0.57Yorkshire Water 0.75Anglian Water 0.68Severn Trent 0.65-0.74South West Water 0.81South East Water 1.00Southern Water 0.58-0.60North Surrey Water 0.62West Hampshire Water 0.56Thames Water 0.60Portsmouth Water 0.41

Some more recent figures showing water prices in different UK regions in 2000 are shown in Table 5.

Table 5 - Water Company prices paid by nurseries in 2000 (Source: Bulrush Peat Company Ltd.)

Region Price paid £ per m3

Stratford 0.76Essex 0.62Cambridgeshire 0.64Kent 0.75West Sussex 0.44-0.65East Sussex 1.14Cheshire 0.62Lanarkshire 0.46Inverness 0.68


European growers are less reliant on mains supplies for their water. Examples of the costings in some European countries are shown in Table 6.

Table 6 - Water costs for European growers (Molitor, Van Oost, Van Tol, pers. comm.)

Country Cost of mains water (£/m3)

Sources used on nurseries

Germany 1.25 - 1.57 Mains or borehole water which can cost (£0.13/m3)

The Netherlands

Mains: 0.55 - 0.82Bassin:0.27 - 0.55

Protected crops growers mainly use bassin and recirculated water. Outdoor producers tend to use recycled or dyke water which is free apart from the taxes paid towards dyke maintenance.

Belgium Mains: 0.48Wells: free but taxed at 0.03

Most nurseries extract from groundwater.


4.2 Irrigation Systems Costings

Any system adopted by growers must be financially viable to install and maintain. Water efficiency benefits have to be weighed up against financial implications. In this report, costing estimates for ten different systems for protected ornamentals have been produced. Systems vary immensely between nurseries and in order to make this excercise comparable a number of assumptions have been made:

1. All systems are supplied by the water mains into a galvanised water tank direct to the glasshouse.

2. Water is costed at 0.61 pence per m3.3. Any filtration of the mains water occurs before entering the glasshouse, unless

specified for the system.4. Any acidification of the mains water occurs before entering the glasshouse, unless

specified for the system.5. Adequate pressure is available to drive all systems.6. All systems are fitted into a 1 acre (4047 m2) 6.4m Venlo glasshouse. A total of

12 bays, 52m long with a central path running the length of the glasshouse.7. Construction labour charged at £225 per man day.8. Watering labour charged at £52 per man day.9. The costs are based on summer 2000 list prices.10. Glasshouses are used for 40 out of the 52 weeks of the year.

A summary of the costings is shown in Table 7. Full details of the costings are shown in Appendix XX and Table 7 should be read in conjunction with this.

Table 7 - Summary of system costings based on above assumptions

System Set up cost per m2 (£)

Annual running cost (£/m2)

Ebb & Flow Floor (Recirculated) 28.60 0.51Ebb & Flow Floor (To waste) 27.80 1.12Ebb & Flow Benches (Recirculated) 33.29 0.48Ebb & Flow Benches (To waste) 32.39 1.00Gantry 23.18 0.67Overhead 1.71 1.01Hand-watering 0.46 1.38Capillary Matting 2.24 1.02Drip 2.92 0.39Trough Track 26.63 0.83

N.B. costs will vary considerably depending on the type of glasshouse, crop grown and utilisation. When considering installing a new irrigation system, an irrigation consultant or company should be consulted to plan specific needs accurately.

The costings were calculated for each system following consultation with nurseries using each system, manufacturers and suppliers. It was assumed that standard fittings and equipment were used in each case and summer 2000 list prices were used.


4.3 Water Treatment for Preventing Disease Spread - Methods and Costings

Contaminated water can be a major source of plant infection, especially by phycomycete pathogens such as Pythium and Phytophthora spp.. It is therefore important to maintain good hygiene in water supply systems whatever the water source used. Whenever practicable, maintenance of plant quality by excluding plant pathogen propagules from production systems, (i.e. ‘prevention rather than cure’) is the best course of action. Water sources with a high risk of contamination with pathogen spores are those derived from surface water such as rivers. However, water from greenhouse roofs and even bore-holes can contain infective pathogen propagules. Perhaps the greatest risk of contamination with plant pathogens comes from collecting and recycling irrigation water. Research funded by MAFF at HRI on disease spread in production systems recirculating used water, demonstrated that:

Disease spread was rapid when inoculated plants were introduced to recirculating systems in a broad range of plant species and production systems (i.e. pot plants in ebb/flood systems, containerised HNS on gravel beds, rockwool and NFT tomatoes and cucumbers and cut flowers in aeroponics, NFT and sand bed systems. Disease organisms shown to spread rapidly in such systems included, Phytophthora, Pythium, Thielaviopsis, Fusarium and Colletotrichum spp.).

Although infection was usually widespread, symptoms often were not as severe as might be expected from previous ‘run to waste’ experience. This is possibly not a problem where the yield consists of cut stems or fruit, but when the root system is part of the product as in pot plants, the presence of sub-clinical infection could cause problems once plants leave the nursery.

Treating recycled water before re-use successfully stopped the spread of infection and can significantly reduce disease symptoms. (NB water treatments have not been compared on a large scale in ebb/flood systems, which, depending how they are operated, can have an increased risk of plant-to-plant disease spread).

A number of water treatments have been shown to control disease spread successfully in recirculating systems, including: UV, ozonation, pasteurisation, microfiltration, the addition of chemicals (e.g. chlorination or additions of peroxy acetic acid (PAA)), and slow sand filtration (SSF). Of these, UV, ozonation, pasteurisation and microfiltration technologies are commercially available with ‘off the shelf’ units which can be installed following the suppliers advice. This is also true for chlorine dosing equipment for which there are long-standing dosing guidelines available from manufacturers of dosing equipment. There is also much useful technical information available on chemical sterilants through an HDC review (O’Neill and Berrie, 1992 HDC CP 4). At present, PAA is not registered as a pesticide and so cannot be used for disease control by dosing water. However, it is a very useful disinfectant with low phytotoxicity and can be used for cleaning beds and equipment between crops when a fast turn-around is needed. Guidelines are also available for the operation of SSF following MAFF and HDC funded research at HRI (Pettitt, 1996 MAFF HH1708SHN, 1997 HDC HNS 88, 1999 MAFF HH1733SHN, 2000 and unpublished HDC HNS 88b) and these will be considered further here. Many of the general guidelines for SSF costing, installation and operation apply to all water treatment


techniques and where relevant these similarities will be pointed out in the following notes:

Water treatment techniques can be described as either ‘active’ or ‘passive’ disinfection (McPherson and Harriman, 1995). Active disinfection (e.g. UV, ozonation, pasteurisation or addition of chemicals) tends to kill all members of the microflora in the water indiscriminately, whereas passive treatments (e.g. microfiltration and SSF), do not completely remove certain groups of organisms such as fluorescent pseudomonad bacteria which are thought to play a role in reducing plant disease. Both types of system are effective at removing pathogen propagules from recirculated water, but current thought favours the use of ‘passive’ treatments in production systems where there is the possibility of introducing pathogen propagules from sources other than the water (e.g. plant material imported onto the nursery). The reason for this is that ‘active’ disinfection tends to reduce natural disease suppression downstream, whereas ‘passive’ dissinfection does not (and may even stimulate it in the case of SSF). There is still much we do not understand about natural disease suppression in irrigation water and research is continuing in this area.

The basic requirements for a system set up for cleaning recycled water include:

(i) a collection tank for water to be recycled,(ii) water treatment system and(iii) storage facility for treated water.

The sizes of these three components will be decided by:

a) the volume of water to be recycled/treated,b) the recycling strategy,c) the size of the production area andd) the type of irrigation system being usede) the water treatment system to be used.

The recycling strategy directly affects the volumes and quality of water to be treated. For example, if only the surplus water from an ebb/flood system is to be treated, the volumes of water for treatment would be much smaller than in a system where surplus water from beds is collected and treated together with greenhouse roof water. The quality of the waters in this example would also be very different in terms of EC, nutrient concentrations and the concentrations and composition of their microflora including potential plant pathogen propagules. Water quality is an important factor and will be briefly considered below.

The other aspect of the recycling strategy that will affect the volumes to be treated is whether recycling is intended to largely replace water usage from other sources such as mains and borehole, or merely to supplement it and minimise nursery runoff. The latter choice would obviously require a smaller treatment installation. If a replacement strategy is to be adopted then the sizes of the horticultural production area and the water source(s) to be recycled are deciding factors on the water volumes to be treated. In addition the irrigation system will greatly affect the volumes of water required as well as the volume and quality of the excess, recyclable water. Finally, the water treatment system will have some influence on decisions about the


size of the storage facility for treated water. The size/capacity of the water treatment system and therefore capital and running costs and the space required, will influence the size of the storage facility and vice versa. A smaller treatment unit may not be able to supply the needs of the nursery on demand. However, if these systems are run continuously to a suitably-sized storage tank they would be satisfactory. This is essentially an economic decision based on treatment unit price, running costs and the availability/volume of clean water storage space.

It is wise to store treated water before use for two reasons:

a) to provide a ‘buffer’ for the inevitable times when ‘troubleshooting’ is needed on the treatment system (inevitably the hottest day of the summer!),

b) to provide a buffer’ between treatment and application to crops, so that in the event of a suspected treatment breakdown, potentially contaminated, or chemically overdosed water is not applied directly to crops before testing and ameliorative treatment can be implemented.

Under ideal conditions a useful rule of thumb would be to set the size of the clean water storage to the volume of maximal (‘worst case’) daily demand plus a safety margin. However, the space available for such storage facilities is often limited, necessitating higher water treatment flow rates and possibly, therefore, larger treatment units and higher treatment costs.

In the case of SSF, the volume of water treated is directly related to the filter surface area; 1 m2 of filter surface area will produce between 1 and 3 m3 (approximately 220-660 gallons) per day depending on the sand quality used. More detailed information on filter structure and sand qualities is available in HDC reports HNS 88 and 88a (Pettitt, 1997 and 2000). It is very important to note that SSF is a biological process and requires oxygen, consequently the flow of water through the filter must be continuous. Storage space for the cleaned water is therefore essential for SSF operation, to store the water treated during times of the day (and night) when demand is low. Some commercially available SSF packages operate on an intermittent flow. However, observations at HRI Efford, of both experiments and samples from such systems on commercial nurseries, have shown that switching the flow on and off through a SSF often results in a breakdown in filter efficacy.

The decision as to what type of treatment system to use is ultimately going to be based on a combination of desired cleaning approach (i.e. ‘active’ or ‘passive’), available space and treatment capital and running costs. The principles of water treatment installation are essentially the same whatever system is likely to be selected, so only SSF is considered here.

A SSF system would be installed between the dirty water and treated clean water storage facilities. Three aspects of the quality of the dirty water can influence the operation of the cleaning treatment:

1. suspended particles2. oxygenation3. electroconductivity (EC).


The most important of these is the amount of suspended particles, such as silt or peat fines, in the water. These need to be removed by some form of pre-filter (pre-filtration is a topic being dealt with in HDC-funded research at present: HDC HNS 88b). Pre-filtration is important for most water treatment systems, for example small suspended particles can cause ‘shadowing’ in UV systems, they can also sequester added chemicals and reduce their efficacy. In the case of SSF the problem is one of filter blockage.

Oxygenation and EC are both important with SSF action. As mentioned above, the biological action of SSF is aerobic and therefore it is necessary to make sure that oxygen levels are reasonably high in the water to be treated. This is easily achieved by splashing the water into the top of the filter. The effects of EC on SSF biology are not understood and this is an area that requires more research. High ECs (6 mS or more) have been linked to breakdowns in SSF efficacy. In the study reported here, nursery effluents only exceeded this on one nursery on a single occasion. The simplest way to deal with high ECs is dilution with water and if the rainwater is collected from greenhouse roofs for recycling, this is not a problem.

As outlined above, the size of the filter to be installed is decided by the planned capacity for storage (if this is limiting) or (better!) the maximum likely daily water demand. To this value, a ‘safety margin’ may be added. A conservative estimate of SSF flow rate would be 0.15 mh-1, so the surface area of filter required to produce the desired volume of treated water in 24 h of running can be calculated in m2 by:

((a + b) ÷ 24) ÷ 0.15

where: a = maximum daily water demand (m3) and b = ‘safety margin’ (m3). Using this simple formula, the sizes of filters needed to treat 60, 100 and 250 m3day-1 can be estimated as 18.3, 30.6 and 76.4 m2 respectively, given a 10% ‘safety margin’ (i.e. if circular tanks were used to house these filters, their diameters would be either, 4.8, 6.2 or 9.8 m respectively). More in-depth descriptions of SSF structure and function can be obtained from HDC reports HNS 88 and 88a (Pettitt, 1997 and 2000) as well as HDC workshops (contact Fiona Sheppard at HDC)

Installation costs for SSF can vary considerably depending on whether the filter is installed by contractors or ‘home built’. Commercially installed systems can cost anything from £10,000 to £30,000, depending on size and ‘extras’ such as pre-filters. Substantial savings can be made on this if the filter is constructed using on-site plumbing expertise, although staff time needs to be considered. Recent experience with a ‘home-built’ filter capable of processing 100 m3 per day resulted in a total installation cost of just over £7,000. In addition to installation, the running costs need to be considered. The running cost that all treatment systems have in common is the power required to pump water from the dirty storage to the treatment system and from there to the clean storage. In addition to this, UV and ozonation systems require electric power to operate, and chemical dosing systems require a small amount of electricity plus a supply of chemicals. SSF may need cleaning occasionally (a simple process described in Pettitt, 1997 HDC HNS 88), although this need not be more frequent than once per year if the pre-filtration is working well.


Currently research on cleaning irrigation and feed water is focusing on two areas. Firstly there are the practical aspects (funded by HDC) of system operation, for example assessment of pre-filtration systems for water treatment systems. This work is being backed up by strategic work (largely funded by MAFF) looking into the biology of natural disease suppression in irrigation and biofiltration systems with a view to improving efficacy of operation. In particular this work is focused on attempts to increase SSF flow rates, which if successful would ultimately lead to future reductions in SSF size.


5. LEGISLATION AND PRACTICE IN OTHER COUNTRIES

5.1 The Netherlands

The detail of Dutch environmental legislation was given in HDC project PC 59a (Briercliffe, 1998). Since PC 59a was written Dutch growers are under further pressure to reduce pollution in accordance with targets being introduced between now and 2010. The law relating to glasshouse horticulture (known as AMvB) gives growers targets for reducing nitrogen, phosphorous, pesticide and energy pollution. Considerable negotiation is ongoing between the Dutch government and growers as to what these targets should be (Voogt, pers. comm.).

Individual nurseries are responsible for their own ‘Company Environmental Plan’ (CEP or BMP in Dutch) which is one popular method of conforming with the legislation. In this plan, growers make an agreement with the local authorities, to invest in certain equipment, training, etc., and state how this will help them to meet their agreed targets. As targets are set for nutrients, pesticides and energy, growers can work on one at a time if they wish. For example they can agree to invest in some new energy saving equipment one year and then agree on a different target area the following year.

This ‘covenant’ between the government and growers, known as GLAMI (GLAsshouseMIlieu) itemises detailed targets for each crop and type of growing system (Stanghellini, pers. comm.). The targets are presently being re-negotiated and are not yet published but examples of the current targets are shown in Table 8.

Table 8 - Targets for maximum permitted application or use levels by 2003 and 2010 (du Mortier, 1999).

Crop Pesticides (kg active substance)

Energy (GJ/ha)

Nitrogen (kg/ha)

Phosphorus (kg/ha)

Target year 2003 2010 2003 2010 2003 2010 2003 2010Poinsettia 21.0 19.8 14640 13580 449.8 412.0 51.6 50.3Rose 62.1 53.9 24143 21355 1098.8 872.0 215.6 203Chrysanthemum 54.1 49.4 12945 11466 707.6 493.1 62.7 52.5

Although the targets are designed to reduce emissions they work by setting input targets. Measuring inputs within a particular growing system, is the only way of ensuring that growers are changing practices to conform with legislation. Growers are finding the pesticide targets particularly difficult to reach. For reducing nutrient pollution, the emphasis has moved away from targeting water application to specific restrictions on fertiliser use.

Growers are still very concerned about the targets. As production systems improve and become more intensive then the fertiliser application per given area may increase rather than decrease although the overall use (i.e. per volume of crop produced) will have reduced. The negotiations on these subjects will continue between Dutch growers, through their grower organisations and the government.


The government is largely using the MPS (Milieu Project Sierteelt), environmental accreditation scheme, for policing the legislation. Members of MPS must record all crop inputs and demonstrate reductions over time. At present 90% of Dutch growers are members of MPS. The remaining growers are not regulated by the scheme and therefore incur a higher risk of unannounced ‘visits’ from the local authorities.

The Dutch research stations are continuing to help growers comply with the legislation. Researchers at IMAG in Wageningen are aiming to use what is known about flows of water and pollutants in different crops to help growers achieve the GLAMI covenant targets. This will probably extend to research projects to help growers to further reduce their use of pesticides, fertilisers and energy (Stanghellini, pers. comm.)

This improved fertiliser and water application research has also been developing at the Proefstation voor Bloemisterij en Glasgroente (PBG) Naaldwijk (Voogt, pers. comm.). Their research has been done on nutrient losses from soil-grown glasshouse crops. Through use of careful fertigation fertiliser can be applied to these crops without leading to leaching to ground or surface waters (Voogt, et al., 2000, in press). Research is also being done on the use of soil moisture measuring equipment as described in Section 2.1.

5.2 Germany

Legislation

The German public are very concerned about environmental issues. This is reflected in the German Parliament where the Green Party have been a significant force for the last fifteen years. The emphasis of German environmental law focuses more on quality than quantity. The government does not restrict water consumption although constitutional law does empower the government to do so if there is an extreme problem such as a severe water shortage. Currently there is not a water shortage in Germany (Freimuth, pers. comm.). However, the government has reduced water consumption through high charges. German households in some Landre (Regional Authorities), pay 13.50 DM/m3 for water (supply and waste disposal); this is equivalent to £4.23 at the March 2000 exchange rate. Growers do not pay this rate unless they source from the mains and return waste to the mains system. However, growers using the mains supply still have to pay 4 - 5 DM/m3 (£1.25 - £1.57) which is significantly higher than most UK growers. Water sourced from boreholes can cost up to 40 fenigs/m3 (13p/m3).

The main emphasis of German legislation is on pollution. It is illegal to pollute surface or groundwater in any way. The aim is for zero pollution but in reality this is virtually impossible to achieve. For those using nutrients, it is illegal to allow them to reach ground or surface water. For growers planting in the soil ‘Good Agricultural Practice’ must be followed. This states that soil must be tested before nutrient application. Tests should be carried out for phosphate every five years and two to three times each year for nitrate. The legislation applies to growers with more than 10 ha of land under outdoor or protected production. The legislation does not apply to container producers although these growers are encouraged to apply the same


principles to avoid having more legislation imposed. The grower must pay for the tests although some landre initially helped growers by paying 50% of the costs.

The areas of particular concern have been designated ‘Water Protection Zones’ (Briercliffe, 1998. HDC Project PC 59a) which include the main horticultural production areas. The degree of controls imposed within these zones, depends on the proximity to the well or water source. The restrictions in these zones are defined as follows:

Zone 1 No irrigation within 30 m radius of the well.

Zone 2 ‘Closed’ production systems only.

Zone 3 These are much larger areas and restrictions will depend on the risk to water. Controls will relate to nitrate and pesticide applications.

Within these zones the water industry, which is state run, has sought to work with growers to reduce the threat to water. This has been done in some regions, by employing a horticultural consultant to work with growers to help them comply with the legislation and implement any changes. The standards of cleanliness demanded from the German water industry are far higher than those in other EU member states and significantly stricter than those laid down in the EC Drinking Water Directive. In order to meet their obligations, the water authorities can exert pressure on consumers and polluters through pricing and media publicity. They can easily ‘name and shame’ water users considered to be unhelpful in their quest for clean water.

Germany also has other laws covering soil protection and pesticides. More legislation is expected including an all embracing ‘Environment’ law which will bring together the various strands of related legislation. This will undoubtedly introduce more regulations which will affect growers.

Enforcement

Environmental legislation is enforced by a national ‘Environmental Agency’ as well as by agencies within each of the sixteen federal states. The legislation is not easy to enforce as the requirements are so unrealistic but enforcement is tightening up particularly within the Water Protection Zones.

Changes in production methods for protected ornamentals

German growers have responded to environmental legislation and water costs by installing ‘closed’ systems where there is no nutrient release to the environment. It is estimated that 60-70% of protected ornamentals nurseries are using closed systems (Molitor, pers. comm.) and virtually all investments over the last 10 years have been in closed systems. The government did provide financial help to growers to convert to closed systems in one of the German landre. Growers were offered 40-50% of the investment costs. This was gained through a tax on consumers of 10 pfennigs/m3 of water used, which was to be invested in water saving. However, this financial help is no longer available and no other grant schemes exist.


Most research work is based on the use of closed systems. Research on minimising water application to reduce leachate is not justified as it is not considered to be a commercially significant issue. Closed systems tend to be either ebb and flow flooding systems or overhead applications where water is collected and recirculated. Nurseries only treat recirculated water (for pathogens) when sub-irrigation systems are not used. Researchers at Geisenheim, along with German growers, are convinced that disease spread does not occur in sub-irrigation systems when healthy crops are not excessively irrigated. They claim that water does not leave a pot once it is taken up and therefore there is no potential for pathogen spread. This agrees with work carried out in the USA (Reed, 1996). Overhead systems do require water treatment and most growers use slow sand filtration technology. Some growers have more recently found granulated rockwool in slow filters to be more effective than sand.

The focus of research in Germany is on reducing nutrient losses. Although this is largely achieved by reducing water consumption the benefits of water savings are not the main focus. However, there is considerable interest in the use of tensiometers. Growers are increasingly using this technology to reduce water consumption but, perhaps more significantly, to control crop growth. Typically growers insert a tensiometer into one reference plant within a growing area (with the same conditions and crop). The tensiometer is used to trigger the onset of irrigation when, for example, the tension reaches 120 kP and then switch off when the tension drops below 50 kP. The reference plant used would represent the plant with the highest water consumption to ensure all plants are adequately watered.

Research has been carried out at Geisenheim using tensiometers on Poinsettia and Pelargonium to assess crop growth in different water and fertiliser regimes. There are many implications for crop growth and models are being developed for using water application to control crop growth. The regime for greatest restriction on Pelargonium (plants kept at 400 ha/Pa) led to more water being taken up at each watering but overall a third lower water consumption by the crop.

Some problems were experienced with Poinsettia crops where low water regimes caused leaf scorching and uneven branching so clearly more work is required to develop models for control of plant growth by water use.

5.3 Australia

Due to the hot climate and scarcity of water, growers in Australia are under pressure to reduce water use. Legislation that relates to nursery run-off has been developed on a regional or state basis, therefore not all areas are under the same legislation. The area with the toughest specific legislation on this subject is New South Wales (NSW). In other areas, such as Victoria, the industry has been given time to ‘self regulate’ (Hall, pers. comm.).

It is likely that any new legislation will focus on nurseries as ‘point sources’ for pollution. The state Environmental Protection Agencies (EPA) have identified nurseries and retailers as potential point source polluters and the industry is aware that it needs to deal with waste water. Up to 70% of nurseries treat their waste water before re-using it or allowing it to leave the nursery. Growers have to demonstrate


that they are willing to put effort into reducing contaminated waste water in order to avoid the introduction of specific legislation (Hall, pers. comm.).

The possibility of fines coupled with the increasing price of water is making growers look seriously at the issues. Growers can see the advantages in adopting closed sub-irrigation systems from both a financial, environmental and marketing point of view. Industry accreditation schemes are also helping to focus the minds of growers on the issue (Hall, pers. comm.). The Nursery Industry Accreditation Scheme, Australia (NIASA) requires that all irrigation water, from surface supplies and re-used water, be effectively disinfected. NIASA is a scheme for all growers of nursery stock and growing media suppliers (Atkinson, pers. comm.).

In response to these pressures the use of sub-irrigation systems is slowly being adopted. As in the UK this tends to be a combination of ebb and flood, capillary matting, sand beds and drip systems. However, many nurseries are simply trying to make their overhead systems more efficient. ‘Water Works’ workshops carried out by the regional extension services have been particularly effective in helping growers to do this. Many growers have achieved 30% or better reductions in water use along with improved crop uniformity as a result of applying the recommendations (Atkinson, pers. comm.). An evaluation of the workshops showed that 70% of systems are applying water at a higher rate than the potting media can absorb, producing excessive nutrient leaching. It showed that 87% of systems are applying water so unevenly that about two to three times the water volume is required to effectively water the plants. Only 7% of the systems tested were using water efficiently enough to implement scheduling techniques and obtaining maximum benefit from fertiliser applications (Rolfe, 1998).

Some growers collect run-off and treat it using various methods before re-use. The methods most commonly used include chlorine, chloro-bromine, chlorine-dioxide and UV. As in the UK Australian growers are beginning to develop slow sand filtration and adopt this for water treatment (Hall, pers. comm.).

On the whole it seems that Australian growers are at a very similar stage to those in the UK. Most use ‘open’ systems, usually applied overhead although increasingly they are turning to some form of sub-irrigation. They are addressing the issues of water management seriously. This can be seen from the publication of ‘Managing Water in Plant Nurseries’ (Rolfe et.al, 1994) which is a substantial book designed to help growers in this area. The book was funded by industry research funding and a new edition will soon be available. Other booklets have also been produced on this subject from industry research levy funding (Atkinson, 1997).


5.4 USA

As in Australia, the responsibility for environmental protection lies with individual states. Some states, such as Oregon, have strict controls over nutrient leaching to land and water courses. Many irrigation systems in the USA are overhead although there is an increasing use of ebb and flow flood benches in pot plant production. Research work and guidance for US growers on this subject is typically carried out by the University Extension Services in different states. Those in Oregon, Massachusets and Texas have been particularly active in promoting this work. Much of the work cited in Section 2.1 was carried out in US Universities.

This research has focused on reducing water application through the type of irrigation system and reducing fertiliser leaching by the same means. Extensive work has been carried out in the USA on controlled release fertilisers (e.g. Cox, 1993) but results from the USA and Australia may not be directly applicable to the UK situation. The differences in temperatures, light levels and humidities affect water and fertiliser use and results will not always be the same in the UK.

Many Extension services produce guidance notes for growers on the subject of water and fertiliser conservation and publications; Cox (1996) provided a useful overview of research to growers. In many states growers are now under pressure to recycle water (Sheldon, 2000; James and van Iersel, 1998) either through legislation or for quality reasons. Many of the recommendations in Section 8.3 come from learning experiences in the USA. An example of this is highlighted in a survey carried out on growers using ‘zero-effluent systems’ (i.e. ebb and flow flooding systems, Wen-fei, et al., 1998). The survey showed that growers that had installed zero-effluent systems had done so primarily to improve crop quality, increase production efficiency and to provide greater control over the production system. Legislation and environmental concerns were not considered to be as important. Of the growers recirculating water 84% did not treat it for disease before re-use. Of these, 78% had never had pathogen problems as a result, 20% said that disease levels had been reduced by using the zero-effluent system and only 2% reported disease problems attributed to the use of untreated recirculated water. Of those surveyed 83% reported reduced fertiliser applications as a result of the new systems and 83% said that installation of the zero-effluent systems would pay for itself although this may take a few years.


6. EXISTING AND PROPOSED LEGISLATION IN THE UK

This section outlines some of the existing and proposed legislation which could affect growers. However, expert advice should be sought before taking any action which could result in pollution, or if there is any doubt about the legality of current practice. This section repeats the relevant information provided in PC 59a (Briercliffe, 1998) and updates other areas as appropriate.

Summary of legislation implications for protected ornamentals growers

As shown in this section, there is a considerable amount of legislation relating to nitrates; most is in an agricultural context, with smaller scale horticultural enterprises being less affected.

Most of the legislation against water pollution either regulates large scale agriculture or large industry and sewage works. Figures are given in the Nitrate Directive for values of N per hectare which should not be exceeded, this covers both direct application to soils and soil-grown crops. However, no provision is currently made for protected ornamentals or containers as far as nutrient regulation is concerned.

Although fertilisers are rarely applied directly to soils in protected ornamental production, there can still be considerable run-off of nutrients to the ground. The area under protection can become a point source of pollution, possibly exceeding agricultural levels. Therefore, the following aspects of legislation should be adhered to:

Water Resources Act 1991 - follow the new horticulture sections in the MAFF ‘Water Code’

Groundwater Regulations 1998 - Ensure that these regulations are complied with and listed pesticides and fertilisers are only disposed of onto authorised sites.

FEPA - Prevent water contamination with pesticides by following the regulations.

Drinking Water Directive - Ensure run-off is not causing nitrate levels in adjoining watercourses to exceed the limit of 50 mg/l nitrate.

Water Abstraction Licensing - Obtain a copy of ‘Taking Water Responsibly’ from DETR and plan future abstractions and water uses in the light of these proposals.

Horticultural enterprises should be seen to be minimising nutrient and pesticide run-off in order to prevent heavily enforced legislation being imposed in the future. However, in preparation for enforced legislation, growers need to be ready and have a strategy to reduce nutrient and pesticide waste.

Laws Controlling Pollution


Water Resources Act (WRA) 1991

Water pollution control is mainly governed by the Water Resources Act (WRA) 1991. The legislation stipulates that:

1. Prosecution will occur if pollution is detected.

2. Measures to prevent pollution must be taken. The Environment Agency (EA) is responsible for enforcing this legislation.

Section 85 of the Water Resources Act 1991 makes it an offence to cause or knowingly to permit a discharge of poisonous, noxious or polluting matter or any solid waste matter to enter controlled waters. It is also an offence to allow matter to enter water so as to obstruct flow and aggravate pollution. “Controlled waters” means all ground water, coastal or inland waters including rivers, streams, ditches, land drains and most other passages through which water flows, and most lakes and ponds (Anon., 1992). One can “cause” pollution without acting intentionally or negligently.

However, an offence is not committed under Section 85 if authority to make the discharge has been given. This usually means a consent to discharge issued by the EA under Section 88 of the Act. In practice few farmers apply for discharge consents. The strengths of the wastes involved, the lack of dilution usually available, and the costs of treating the wastes to a form that might be acceptable to discharge, make it unlikely that an application for a discharge consent for most farm wastes would be acceptable to the EA (Anon., 1992). Situations where wastes may be discharged to controlled waters under a discharge consent include intensive livestock units, which may be able to justify the costs of a treatment plant; and where the polluting effect of the waste is relatively weak, e.g. with vegetable washings.

Consents to discharge may be reviewed and the EA has a duty to review them periodically. This may result from circumstances in, for example, an individual river or by the Government responding to European Directives on water quality.

Groundwater Regulations 1998

The Groundwater Regulations came into force on 1 April 1999. They were introduced at relatively short notice as the government sought to comply with the EC Groundwater Directive. The Regulations were primarily initiated following concern about pesticide pollution from disposal of spent sheep dip. The Regulations affect all growers that dispose of any type of pesticide to land. Disposal of waste pesticide (including tank washings) to land is prohibited unless it has been authorised by the EA. Growers who applied for authorisation prior to 31 March 1999 can continue current practices until they receive authorisation (which will contain conditions) or their applications are refused (Briercliffe, 2000). These new regulations group chemicals into two lists; List I consists of the more harmful substances, including pesticides and List II lists other substances of concern. Ammonia, nitrites and phosphorus are in List II; these are substances which may be typically released from horticultural premises. The proposed regulations state that an authorisation to introduce these substances into groundwater, shall not be granted in relation to:


1. Any direct discharge of any substance in List I or II.

2. Any disposal or tipping for the purpose of disposal of any substance in List I or II which might lead to an indirect discharge of that substance.

3. Any other activity on or in the ground which might lead to an indirect discharge of any substance in List I or II.

Such authorisation is not granted unless that activity has been subjected to prior investigation. This prior investigation is the responsibility of the EA which has the powers to grant authorisations. Growers are advised, in the first instance, to contact the local office of the EA. However, the main areas where the regulations affect growers are as follows:

The disposal of pesticides to land, including the disposal of washings. This practice must either discontinue (by careful calibration and application of washings to the crop) or the disposal site must be authorised.

The discharge of unused fertiliser solution (i.e. any solution containing List II substances) must be authorised by the EA. This affects growers that use recirculating systems which need an annual cleaning out. Authorisation for this is required unless the grower can demonstrate that the discharge of this solution onto land is of direct agricultural benefit.

Where run-off collects in a drainage or ditch system, before draining into the ground or water courses (drainage into a mains supply should already have authorisation). This drain or collection system requires authorisation from the EA. This is of particular concern as any point source of discharge requires authorisation. This is an area that the EA have not yet confronted individually. However, as other aspects are dealt with then the EA will implement the regulations in full.

General run-off (which is not collected) may also require authorisation. However, this gradual seepage of List II substances is of a lesser concern to the EA. There is scope, within the regulations, for the production of codes of practice which may, in time, cover issues such as this. In all cases growers should contact local EA offices for clarification on particular circumstances.

The authorisation will be granted as long as the conditions are met. These conditions can be extensive and include precautionary measures, maximum quantities and arrangements for monitoring. The cost of this authorisation procedure will be borne by the one seeking to make the disposal (i.e. the grower).

Since the introduction of these regulations the EA have had a number of problems with horticultural businesses. Many of these holdings are relatively small and do not have much land area available for pesticide disposal. The EA prefer to see waste disposed of over large areas to help reduce the concentrations in small areas. Where appropriate compromises cannot be found then authorisations will not be granted and growers will be required to find alternative methods for the disposal of listed substances.


Pollution offences are regarded very seriously and carry a penalty of up to £20,000 in the Magistrates court and an unlimited fine in the Crown court. It may also be necessary to pay for any damage caused by the pollution.

Other discharge legislation within the Water Resources Act

Section 85 of the Water Resources Act does not automatically cover all types of discharge, including discharges to land and certain lakes or ponds. However the EA can prohibit such discharges in particular cases by issuing so-called “relevant prohibitions” under Section 86. This power is limited to discharges “from a building or from any fixed plant” - a restrictive definition which raises complications in the case of certain farm waste disposal systems (Anon., 1992). The Groundwater Regulations, described above, extend the EA’s powers in dealing with discharges to land.

Section 93 and schedule 11 contain powers to designate “Water Protection Zones”. Activities likely to result in water pollution can be restricted in these areas. The EA is responsible for proposing designations to the Secretary of State. This would be in addition to the existing Nitrate Sensitive Areas and Vulnerable Zones (see below).

Section 161 allows the EA to carry out operations to prevent or clean up pollution and recover the costs from the person responsible (the “polluter pays” principle). Under Section 202 the EA can ask farmers and growers for information which will assist in carrying out its job preventing water pollution.

Section 97 provides for Ministers to approve Codes of Good Agricultural Practice (CoGAP). The latest CoGAP for water was published in 1998 and is a practical guide to help farmers and growers avoid causing water pollution. Non-compliance with the code does not necessarily give rise to civil or criminal liability but it could be taken into account in any legal action. Following the code is not a defence against a charge of causing pollution.

The Code contains a section on specialised horticulture and covers soil-grown protected crops, hydroponic protected crops, container nursery stock, organic wastes, other wastes, mushrooms and watercress. It means that some growers would be advised to implement new pollution measures. For example, the Code suggests that for non-recirculating hydroponic systems growers should be encouraged to measure water application rates to ensure that they do not exceed crop requirements plus a reasonable (<30%) excess. For these same systems, excessive run-off should be avoided by using the following techniques:

1. Measure the quantity of run-off at a representative number of points in each cropping area (the code gives details on a method which can be used for measurement). Compare the measurement with standard figures, where available, of run-off for annual water use. Water application should be reduced if run-off is more than 30% of the water being applied.


2. Make sure the irrigation system is well designed, carefully installed, monitored closely and regularly maintained to ensure that the variability in the amount of water delivered by each nozzle or dripper is as low as possible.

3. The amount and frequency of applications should be adjusted according to the needs of the substrate and growing system. For example, more frequent applications of smaller volumes are needed for less retentive substrates.

4. Addition of nutrients to the water for protected crops should be matched to the crop requirement, particularly stage of growth and time of year.

For hydroponic recirculating systems, the amount of solution in the holding tanks should be allowed to decrease as much as possible before the end of cropping to prevent large discharges when the tanks are emptied.

For containerised nursery stock, the Code suggests minimising run-off wherever possible by using sub-irrigated sand beds if these can be afforded. Or if overhead irrigation is used, the system should be carefully designed to match the cropped area and irrigation nozzles should be regularly maintained to ensure even water application.

The Code suggests that new container areas should be planned with the possibility of water recirculation in mind. It also commends the use of controlled release fertilisers and suggests that the amount of nutrients added to both compost and water should be carefully matched to the production system to minimise the amount lost in run-off. Nutrient levels should be monitored to minimise costs and run-off loss.

The Code does not specifically mention protected ornamental crops which are often not grown in soil or in hydroponic systems. However, the conditions relating to containerised nursery stock and nutrient input would probably also cover protected ornamentals.

The Codes of Good Agricultural Practice written for air (1992) and soil (1993) have also been revised and 1998 editions are available.

The Urban Waste Water Treatment Directive (91/271/EC)

This Directive was introduced to protect the environment from the adverse effects of discharges from sewage treatment works and from certain sectors of industry. It is implemented through the Urban Waste Water treatment (England and Wales) Regulations SI 1994/2841. These define the EA as the competent authority.

The Directive requires the identification of Sensitive Areas using indicative standards expressed in terms of nitrate (95% of samples taken should contain no more than 50 mg/l nitrate), phosphate, dissolved oxygen, plant biomass, clarity, retention time and biological effects. Different criteria are applied to estuaries and coastal waters, still freshwaters and running freshwaters. Waters can only be identified as Sensitive Areas under the Directive, if a qualifying discharge is contributing to problems. In such cases nutrient removal is required, unless it can be shown that this is not the cause.


Whilst this Directive directly targets eutrophication, it is mainly targeted at large sewage works impacting in designated Sensitive Areas. It may come into effect against extreme agricultural polluting sources but does not provide the complete answer for controlling eutrophication. The EU is currently working towards a Framework Directive on Water Resources, which aims to integrate different aspects of policy. This will tie in many of the aspects of different legislation e.g., whereas this directive deals with sewage works and the Nitrate Directive deals with agriculture, the EU are aiming to draw it all together in one Framework Directive. In theory this new framework should not bring about new legislation. However, in practice where laws from more than one country are combined, some changes are inevitable. The framework should give authorities a stronger hand in controlling diffuse pollution and place emphasis back on pollution prevention.

EC directive on water quality for freshwater fish (78/659/EEC)

This Directive sets water quality objectives for stretches of rivers and other fresh waters needing protection or improvement in order to support fish life. These objectives are to be achieved through pollution controls and reduction programmes.

Food and Environmental Protection Act (FEPA) 1985, Control of Pesticide Regulations 1986, and Code of Practice for the Safe Use of Pesticides on Farms and Holdings (1990)

The regulations which have been issued under FEPA Part III set out detailed laws for the approval, supply, storage and use of pesticides. One of the basic conditions laid down for the use of pesticides is that users take all reasonable precautions to protect the environment and “in particular to avoid the pollution of water”. People who use pesticides must be competent and have received proper instruction.

The Code of Practice for the Safe Use of Pesticides on Farms and Holdings (1998) gives guidance on pesticide use and precautions to be taken to prevent water pollution. In particular, the Code contains advice on possible routes for disposing of dilute wastes and washings, highlighting the need to ask the EA for advice where disposal is to land. Similar advice is also contained in the 1998 CoGAP for water. FEPA contains powers to control the levels of pesticide which may be left in any crop, feed or feeding stuff.


Environmental Protection Act (EPA) 1990

The Environmental Protection Act 1990 updates the UK’s pollution control systems. It stipulates a system of integrated pollution control for the disposal of wastes to land, water and air.

Part I establishes integrated pollution control and gives local authorities powers to control air pollution from a range of prescribed processes; Part II improves the laws for waste disposal; and Part III covers statutory nuisances and clean air. A new waste management licensing system was put in place by the Waste Management Licensing Regulations 1994, although most agricultural activities are exempt. The DETR (Department of Environment, Transport and the Regions) is expected to consult on the application of controls to agricultural waste during the summer of 2000. If this exemption is removed it could have a significant impact on growers making waste peat and polythene, for example, to be ‘controlled waste’. It is likely that there will be strict instructions for the disposal of controlled waste although composting will be encouraged. Those using composting as a means of waste disposal will have to inform the EA and demonstrate that this is taking place. It is unlikely that these regulations will class nutrient run-off or excessively applied water as waste.

Environment Act 1995

This Act does not replace the EPA (1990) or the WRA (1992) acts, but was introduced for the main purpose of enabling the setting up of the Environment Agency. It also gives the EA new duties which overarch the EPA and WRA with relation to sustainable development and conservation. In real terms, this means there will be no decisions on functional changes in legislation without the EPA and WRA now considering an extra tier, which includes development and conservation.

Planning Law

Environmental Assessment Directive (85/337/EEC) and the Town and Country Planning (Assessment of Environmental Effects) Regulations 1988

These regulations set out the requirements for the Environmental Assessment of certain major developments for which planning permission is needed. Most agricultural projects are exempt from planning control and hence from the procedures established under the Directive requiring environmental assessment of projects likely to significantly affect the environment. Certain projects may, however, be subject to assessment: these include, for agriculture, projects which involve water management, poultry and pig rearing.

If a grower plans a project which requires Environmental Assessment, he is responsible for carrying out the assessment. If a proposed project is likely to affect water quality or water resources, the EA is interested to see that there are likely to be no adverse effects (Anon., 1992). This applies to clean surface water as well as run-off; large volumes of water are collected from glasshouse and shed roofs and concrete areas during rainstorms and could overload ditches. The EA may require an Assessment to be carried out following a water abstraction application. Carrying out this Assessment can involve considerable cost to the grower and in many cases costs


far more than the other licensing and advertising costs which are incurred. The EA may want to know about the impact of the abstraction on other users, surface water, local geology, hydrogeology and water flows. They may also require ecological and engineering surveys to be carried out. The appropriate body may also be consulted if there are plans to build in an Environmentally Sensitive Area (ESA), National Park, on Sites of Special Scientific Interest (SSSI’s) or on archaeological sites.

Control of the Use of Water

Water Act 1989

Water Resources Act 1991

Most people who need to abstract water from a “source of supply” need an abstraction licence. A source of supply can either be an inland water (e.g. river) or ground water. Abstractions of less than 20 m3 per day, which fulfil certain requirements as to location, do not need a licence. Interestingly this could mean that some nurseries using efficient ebb and flow systems, could operate without a license. For example a typical ebb and flow system needs approximately 4 litres/m2/day. As long as less than 20,000 litres was used per day then an ebb and flow system up to 5000 m2 could be used without a license (Bragg, pers. comm.). It is an offence to abstract water without a license or not to comply with the terms of a license. The EA may impose temporary restrictions on abstraction of water for use for spray irrigation, if an exceptional shortage of rain or other emergency makes that necessary (without having to pay compensation). Such restrictions can only relate to groundwater abstractions where that is in turn likely to affect the flow of an inland (i.e. surface) water (Anon., 1992). At present growers of protected crops are exempt but growers of outdoor nursery stock are not.

Most growers will be aware that the government conducted a consultation on changes to the water abstraction licensing system in England and Wales. Their decisions, following this consultation, are published in a DETR publication ‘Taking Water Responsibly’ (Anon 1999b). These changes are expected to come before Parliament as soon as Parliamentary time is allocated. The consultation was extensive and an exhaustive list of all the changes cannot be made here. It is recommended that growers using abstracted water obtain a copy of the above publication from DETR (DETR Free Literature, Tel: 0870 1226236).

The most significant effect of the changes on protected ornamentals producers will come about during a review of existing licenses. By 2003 all abstraction licenses will be reviewed. During this review the agricultural and horticultural sector cannot expect to be treated more favourably than other industrial sectors, as has been the case in the past. The way that water is used by each abstractor will be reviewed as well as the quantities abstracted. The way in which this legislation will be enforced is not known yet but it is likely that growers found to be using excessively inefficient irrigation systems and those wasteful of water, may have their licenses withdrawn or permitted volumes reduced. Growers not presently using all their permitted volumes may be required to surrender licences that are surplus to requirement. The environmental impact of abstraction will also be considered in all future applications.


It is becoming increasingly difficult to obtain permission to abstract water from ground and surface water sources. It is very rare that summer abstraction licenses are granted and where new abstractions are permitted these tend to be for winter abstraction for storage. Licences can take a considerable time to obtain. Simple abstractions can take six months and more complex applications (i.e. where pump tests are required) can take up to eighteen months. Virtually all new licences are time-limited and it can take some time to negotiate a reasonable time period with the EA.

It is clear that future abstraction will be regulated in much more detail. Rather than granting new permits for abstraction the EA are likely to share out existing authorisations and require significantly more justification for use of abstracted water. This is a major financial consideration for growers not using mains water. Water efficiency will cease to be a side issue and will become increasingly important as authorities seek justification for all water uses.

Nitrate Sensitive Areas Scheme

The NSA scheme provides an opportunity for farmers in certain, selected areas of England, to receive payments in return for voluntarily helping to protect valuable supplies of drinking water. A Nitrate Sensitive Area is an area where nitrate concentrations in sources of public drinking water exceed, or are at risk of exceeding, the limit of 50 mg NO3/l laid down in the 1980 EU Drinking Water Directive and where voluntary, compensated agricultural measures have been introduced as a means of reducing those levels. The NSA scheme consists of 22 areas in England, covering approximately 35,000 ha, over 28 nitrate vulnerable groundwaters. This voluntary scheme has now been withdrawn by the government. Existing members of the scheme will be able to continue until their five year contract is over, after which the scheme will finish.

Laws Relating to Drinking Water Quality

Much of this legislation originates from the EU in the form of Directives. These are instructions to the UK Government, and other EU member states, to take steps in domestic law which will carry out the objectives of the Directive. Environmentally orientated Directives tend to operate by setting standards (e.g. for drinking water quality). The Government, through the EA, then has to meet these standards by taking whatever measures will achieve them.

EU Surface Water for Drinking Directive (75/440/EEC)EU Sampling Surface Water for Drinking Directive (79/869/EEC)

The objective of the first of these Directives is to ensure that surface water abstracted for use as drinking water, prior to treatment, reaches certain standards and receives adequate treatment before being put into public supply; the second deals with quality measurements.

EU Drinking Water Directive (80/778/EEC)


This has been implemented under the Water Industry Act (1991) and the Water Supply (Water Quality) Regulations 1989 and amendments in 1989 and 1991. The Regulations incorporate all the standards (maximum admissible concentrations MACs and minimum required concentrations MRCs) set out in the EU Drinking Water Directive. They also include 11 national standards. In total, numerical standards are set for 55 parameters and descriptive standards for a further two parameters. In addition to these standards applying to water at the time of supply, a number of standards apply to water issuing from treatment works and to water held in service reservoirs within the distribution system.

Statutory responsibility is placed upon the Water Companies, but they are subject to checks by local authorities and by the Drinking Water Inspectorate. Monitoring information must be made publicly available.

The EU Drinking Water Directive (1980) sets standards for various substances in drinking water supplies. For nitrate, there is a “guide level” of 25 mg/l NO3 and a MAC of 50 mg/l NO3. The EU limit refers to nitrate. However, most growers are used to dealing in terms of nitrate-N. To convert from a nitrate (NO3) concentration to nitrogen (N) it is necessary to divide by 4.427. The EU limits thus become 5.6 and 11.3 mg/l, respectively. Values are quoted as nitrogen (N) throughout this report. Often the designation nitrate-N (NO3-N) is used to distinguish from ammonium-N (NH4-N).

The EU Drinking Water Directive also sets standards for pesticides and related products in water. At the time of supply a limit is set of 0.5 g/l for the total of the detected substances and for an individual substance 0.1 g/l. Pesticides are defined as fungicides, herbicides and insecticides and the related products refer to polychlorinated biphenyls (PCBs) and terphenyls. The Directive’s standards were set at the limit of detection for organochlorine insecticides in order to minimise the occurrence of pesticides in drinking water and they were not based on toxicological evidence (Hydes et al., 1992). The World Health Organisation adopts a different approach from that of the European Union. It considers the toxicology of individual substances and recommends a guideline concentration for each substance based on the assumption of lifelong consumption at that concentration.

Nitrate Directive

In December 1991 the European Union Nitrate Directive (91/676/EC) was adopted by member states; this may impact on intensive horticulture. The Nitrate Directive aims to limit nitrate contamination of drinking water and prevent nitrate limited eutrophication. (“Eutrophication” is the term used to describe what happens when the nutrient content of natural waters is artificially raised; there may be excessive growth of aquatic plants e.g. reeds and algae and periodic fluctuations in parameters such as dissolved oxygen and pH).

The Directive states that the application of total nitrogen from organic manure over a whole farm should not exceed 210 kg/ha (170 kg/ha from 19 December 2002). This value includes nitrogen in manures and urine deposited while livestock are grazing. The legislation impinges mainly on arable and livestock farmers and will impinge only within designated Nitrate Vulnerable Zones (NVZs).


The Directive includes diffuse losses of nitrate from agriculture and so excess nutrient allowed to drain into the soil would be covered. Both ground and surface waters are included.

The Directive required that by 1994, “vulnerable zones” were to be designated. These are areas of land draining directly or indirectly:

a) into drinking water sources (both ground and surface water) which contain or could contain more than 50 mg/l nitrate (11.3mg/l NO3-N),

b) into waters which are, or may become, eutrophic (with nitrogen as the limiting factor).

By the end of 1995, action programmes were to be drawn up specifying what farmers in the vulnerable zones had to do to reduce nitrate losses. There are currently 68 NVZs in England and Wales which were designated in 1996. The NVZs place no specific requirements on protected horticulture and do not cover N applications to containerised crops.

The UK has drawn up action programmes, which came into force on 19 December 1998 (Anon, 1999). The action programmes are based on “good agricultural practice”, including rules on:

The timing, rate and other conditions of fertiliser applications, both organic and inorganic, to ensure that the crop does not receive more nitrogen than is economically justifiable. e.g. organic manure application must not exceed 250 kg / ha /year of total N.

Closed periods, e.g. for slurry spreading, and storage capacity to be sufficient to cover the longest period during which application is forbidden. Closed periods for application of N fertilisers to arable land are from 1 Sep to 1 Feb; for application to grassland the period is 15 Sep to 1 Feb. Closed periods for application of organic manures to arable land are from 1 Aug to 1 Nov; for application to grassland the period is 1 Sep to 1 Nov.

The overall quantity of N per ha which may be supplied by animal manure including that deposited while grazing, (normally not more than 170 kg/ha with a higher limit of 210 kg N/ha for the first four years after the measures come into effect).

Further plans to extend NVZs are likely to be put out for consultation during the autumn of 2000 (Marks, pers. comm.). These plans include the monitoring of all freshwaters, not just drinking waters. It is expected that this extended testing will lead to the designation of new NVZs and that the majority of new designations will be in central and eastern England.

Although NVZs do not place any specific restrictions on protected horticultural production, the effectiveness of NVZs are constantly being reviewed. If it was found that the agreed strategies are not sufficiently reducing nitrate levels then other


production areas, including glasshouse production, may also be investigated. It is in the interest of growers to minimise nitrate losses from premises, especially if within a NVZ, to avoid bringing protected horticulture within the scope of the Action Programmes.


7. CONCLUSIONS AND KEY RECOMMENDATIONS

7.1 Conclusions

Growers of protected ornamentals are presently wasting water and money through inefficient production systems. Irrigation tests carried out in this research showed that capillary systems lost between 54 and 89% of the water applied, drip systems lost between 11 and 47%, trough track lost 87%, overhead spraylines lost 55% and hand-watering lost between 8 and 78% (Stage 1 tests, Appendix II).

This ‘lost’ water was either evaporated or lost as run-off from the glasshouse. The water contained liquid feed which was being lost in the same proportions to the environment. The value of the fertiliser wastage was as high as £450 for every 10,000 plants grown in one of the capillary systems tested (Figure 11).

Recirculating systems waste very little water and fertiliser but require higher investment costs. Non-recirculating systems can be modified or treated differently to improve the efficiency of water and fertiliser use. This is highlighted by the range of water losses identified for each system above. Key conclusions on each production system are identified below with greater detail presented in Section 3.4.1.

Ebb and flow and trough track systems should be designed with built-in recirculation. Water tanks should be allowed to run down to low levels before emptying out.

Capillary systems should apply water ‘little and often’ and ensure the use of high quality level matting.

Drip systems offer good water saving potential for pot production as long as drippers are regularly checked.

Hand-watering systems can be efficient if supplemented with capillary matting and careful application by trained staff.

Spraylines are difficult to improve and inherently inefficient. Careful choice of nozzles can help to reduce the loss of water onto paths.

Gantry systems provide well targetted water application. Shutting off nozzles irrigating hard surfaces can reduce wastage.

Water costs remain a relatively minor component of production costs. Based on a mean cost of mains water of £0.67/m3 the cost of irrigating 10,000 plants would be approximately £66 for nursery A, £25 for nursery B, £51 for nursery C and £63 for nursery D. However, in some regions water costs are rising and when water abstraction licences are reviewed many growers may have to turn to the mains for their water supply.

This research has proved to be something of an ‘eye opener’, not least to many of the participating nurseries. It has been interesting to see how little most growers really know about the quantities of water and fertiliser that they use and waste. Some of the findings have been alarming whereas others have given more confidence for improving efficiency in the future.

The industry has been concerned for some time about the pressures of European legislation and how these might be implemented in the UK. Some believe that it is


inevitable that in time the UK industry will have to move to entirely ‘closed’ production methods such as in countries like Germany and The Netherlands. However, this need not be the case if the UK industry acts now to reduce the environmental impact of its activities.

This research highlighted some nurseries where water and fertiliser were clearly wasted and the levels of fertiliser going into the ground may well be high enough to cause ground or surface water pollution if soil types and local geology lend themselves to it. Many of these nurseries would not wish to be branded as ‘polluters’ and fortunately potentially polluting nurseries appear to be in the minority. However, where the appropriate environmental authorities discover these practices then the industry would only have itself to blame if strict legislation was introduced.

UK growers would not wish to be forced to produce in ‘closed’ systems, although many may choose these systems as they offer many advantages for crop production. Growers should carefully consider the options presented in this report and seriously review their current practice. Systems that pollute the environment will almost certainly prompt strict legislation. Small changes in practice today could ensure cost savings in the future. Many businesses in The Netherlands went out of business when forced to move to ‘closed’ systems. The situation would be the same in the UK unless it is demonstrated that the systems and practices used take full account of environmental considerations.


7.2 Key Recommendations

It is important that growers are made aware of the findings of this research to ensure action is taken to reduce water and fertiliser losses to the environment.

Growers should be made aware of the methods that can be adopted to reduce losses by use of alternative systems and changes in practice in existing systems. A series of workshops across the country may help in this and/or carefully designed leaflets or manuals.

Growers need to be made more aware of the role of growing media in managing water and fertiliser application.

A number of capillary matting products and systems are available to growers but there is little independent information on which products growers should use. It is recommended that research is carried out to assess the properties of the products available to aid recommendations to growers.

A range of soil moisture-measuring products are on the market and some growers have ‘experimented’ with them. Research is needed to assess which of these are most effective and how they can be appropriately used by UK producers.

Growers should be encouraged to check the efficiency of their own irrigation systems and include this in training to staff.

Growers should be made more aware of the importance of monitoring water quality and how to interpret laboratory analysis.

Further research is required on using water for growth control in pot and bedding crops and establishing blueprints for individual crops.


8. ACKNOWLEDGEMENTS

Tim Briercliffe, Neil Bragg and Stuart Coutts would like to thank the following for their co-operation in obtaining information and data and contributing sections to this report.

Mr Andrew Fuller, W. J. Findons & Sons, Stratford-Upon-AvonDr Annette Carey, HDC, East MallingMr Mike Marks, FRCA, LondonMiss Ann O’Neill, Bulrush Peat Company Ltd., Northern IrelandDr Ross Cameron, HRI, East MallingDr Tim Pettitt, HRI, EffordDr Ian Clarke, HRI, EffordProf Bill Davies, University of LancasterMr Derf Paton, Pinetops Nursery, LymingtonClovis Lande Associates Ltd., TonbridgeAccess Irrigation Ltd., NorthamptonEvenproducts Ltd., Evesham

Mr Harry Kitchener, ADAS Senior Pot Plant Consultant, CambridgeMr Adrian Jevans, ADAS Horticultural Consultant, WorcesterMrs Samantha Lightfoot-Brown, ADAS Ornamentals Consultant, PortsmouthMrs Susie Holmes, ADAS Senior Soils and Growing Media Consultant, Bognor RegisDr Tim O’Neill, ADAS Principal Research Plant Pathologist, ADAS Arthur RickwoodMr Wayne Brough, ADAS Bedding and Pot Plant Consultant, MaidstoneMr Phil Metcalfe, ADAS Senior Mechanisation Consultant, WolverhamptonMr Chris Dyer, ADAS Statistician, Luton

Dr Ross Hall, University of Melbourne, Victoria, AustraliaMr Ian Atkinson, NIAA, Australia

Mr Jorg Freimuth, BVZ, Bonn, GermanyDr Heinz-Dieter Molitor, Research Station, Geisenheim, GermanyDr Ludger Hendriks, Research Station, Geisenheim, Germany

Dr Wim Voogt, PBG, Naaldwijk, The NetherlandsDr Bert Annevelink, IMAG, Wageningen, The NetherlandsDr Cecila Stanghellini, IMAG, Wageningen, The Netherlands

In addition to those mentioned above there are many growers who allowed the use of their nurseries for the collection of the data in this project. Due to the confidentiality agreed with those growers, their names are not recorded in the project but we take this opportunity of stating our gratitude for their co-operation.


9. REFERENCES

Anderson, L., Wang Hansen, C., (2000). Leaching of Nitrogen from container plants grown under controlled fertigation regimes. Journal of Environmental Horticulture 18 (1): 8-12.

Annevelink, E., (1999). Internal Transport Control in Pot Plant Production. IMAG-DLO, The Netherlands.

Anon., (1970). Chemical quality of farm water supplies. MAFF/ADAS Report.

Anon, (1987). Research must be a major concern of the Ebb and Flow committee. Vakblad voor do Bloemiserij. 21, 75 pp.

Anon., (1992). The influence of agriculture on the quality of natural rivers in England and Wales. Water Quality series No 6, National Rivers Authority, Bristol, 154 pp.

Anon, (1998). An Independent Appraisal of Water Utilisation in the UK Container Grown Nursery Stock Industry. ADAS Report for MAFF.

Anon., (1999). Guidelines for Farmers in NVZs. MAFF Publications PB 3277.

Anon., (1999b). Taking water Responsibly - Government Decisions following consultation on changes to the water abstraction licensing system in England and Wales. DETR Free Publications.

Atkinson, I., (1997). Nursery Industry Water Management - Best Practice Guidelines - Australia 1997. Nursery Industry Association of Australia.

Bakker, R., (1988). Insulation of concrete floors in glasshouses not economically worthwhile at the present price of gas. Vakblad voer de Bloemiserij. 25: 30-35.

Bragg, N. C., Chambers, B. J., (1987). Interpretation and advisory applications of compost air-filled porosity (AFP) measurements. Acta Horticulturae 221: 35-44.

Briercliffe, T. J., (1998). Environmental Impact of Run-off from the Production of Protected Ornamental Crops. HDC Report PC 59a.

Briercliffe, T. J., (2000). Groundwater Regs - How compliant are you?. Grower. 24 Feb 2000.

Cox, D. A., (1993). Reducing Nitrogen leaching losses from containerised plants: the effectiveness of controlled-release ferilisers. Journal of Plant Nutrition 16 (3): 533-545.

Cox, D. A., (1996). Best Management Practices for Nutrient Management. University of Massachusetts Extension.


Gers, W., (1986). Multi-layer growing in glasshouses in the Federal Republic of Germany. Grb + Gw. 24: 1563-1573.

Groves, K. M., Warren, S. L., Bilderback, T. E., (1998). Irrigation volume, application, and controlled-release fertiliser - Effect on substrate solution nutrient concentration and water efficiency in containerised plant production. Journal of Environmental Horticulture 16 (3): 182-188.

Hall, R., Connellan, G., Mayotte, J., (1998). Research supports sub-irrigation benefits. Australian Horticulture April 1998.

Hansen, R. C., Pasian, C. C., (1999). Using tensiometres for precision microirrigation of container-grown roses. Applied Engineering in Agriculture 15 (5): 483-490.

Harmer, E., (1990). Experimental studies change over to closed cultivation systems. Grb + Gw. 24: 1167-1168.

Hydes, O. D., Hill, C. Y., Marsden, P. K., Waite, W. M., (1992). Nitrate, pesticides and lead 1989 and 1990. Drinking Water Inspectorate, London, 80 pp.

James, E., van Iersal, M., (1998). Phosphorus fertilisation in ebb and flow production of bedding plants. HortScience 33 (3): 522.

Lightfoot-Brown, S., (1999). Leave it to reeds. Grower 30 Sep 1999, 132 (14): 25-26.

Meeuwissen, C., (1989). The microclimate and base heating in the growing of pot plants. Vakblad voer de Bloemiserij. pp21

du Mortier, W., (1999). AMvB Glastinbouw geeft tuindersen overheden de ruimte. Vakblad voor de Bloemisterij 32: 12-13.

Morvant, J. K., Dole, J. M., Allen, E., (1997). Irrigation systems alter distribution of roots, soluble salts, nitrogen and pH in the root medium. HortTechnology 7 (2), 156-160.

Morvant, J. K., Dole, J. M., Cole, J. C., (1998). Irrigation frequency and system affect Poinsettia growth, water use, and run-off’. HortScience 33 (1), 42-46.

O'Neill, T. M. & Berrie, A. M. (1992). Disinfection in commercialhorticulture: A review of chemical disinfectants, soil treatment withformalin and water treatment for controlling plant pathogens. Final Reporton HDC CP4, Petersfield: Horticultural Development Council, 184 pp.

Newman, J. P., Lieth, J. H., Faber, B., (1992). Effect of an irrigation system controlled by soil moisture tension in reducing water usage and run-off in Poinsettia production. HortScience 27 (6), 640-641.

van Os, E. A., (1998). Closed soiless growing systems in the Netherlands: the finishing touch. Acta Horticulturae 458: 279-291.


Otten, W., Raats, P. A. C., Baas, R., Challa, H., Kabat, P., (1999). Spatial and temporal dynamics of water in the root environment of potted plants on a flooded bench fertigation system. Netherlands Journal of Agricultural Science 47, 51-65.

Pettitt, T. R. (1996). To evaluate methods of root disease management of HNS, reducing pesticide use. Final report on MAFF project HH1708SHN.

Pettitt, T. R. (1997). Monitoring the commercial development of slow sandfiltration in HNS. Final Report on HDC HNS 88, East Malling: HorticulturalDevelopment Council, 34 pp.

Pettitt, T. R. (1999). Potential of slow sand filters for control of fungalpathogens in recirculation systems. Final Report on MAFF project HH1733SHN.

Pettitt, T. R. (2000). Development of a low-cost pilot test procedure forassessing the efficacy of slow sand filtration on individual nurseries.Final Report on HDC HNS 88a, East Malling: Horticultural DevelopmentCouncil, 33 pp.

Pettitt, T. R. (in preparation). Slow sand filtration in HNS production:Assessment of pre-filtration treatments of water to reduce the frequency offilter cleaning operations. Project HNS 88b Report Due End December 2000.

McPherson, G.M. & Harriman, M.R. (1995). Is recirculation too radical? HDCProject News, June 1995 pp 6-7.

McPherson, G.M. (1996). Evaluation of disinfection systems for the controlof root pathogens in hydroponic crops of tomato and cucumber grown usingrecirculation technology. Final Report on HDC PC60, Petersfield:Horticultural Development Council, 2 vols.

Reed., D. W., (1996). Water, Media and Nutrition for Greenhouse Crops - a Grower Guide. Ball Publishing, Batavia, IL., USA.

Rolfe, C., Currey, A., Atkinson, I., (1994). Managing Water in Plant Nurseries. NSW Agriculture, Australia.

Rolfe, C., (1998). NIAA follows up on the success of the Water Work workshops. Australian Horticulture April 1998: 54-55.

Runia, W., Nadwijk, N. T., (1988). Disinfection of drainage water in recycling systems. Vakblad voer de Bloemiserij. 3: 38-39.

Scharpf, H. C., (1997). Physical characteristics of peat and the growth of pot plants. Proceedings of the International Peat Conference - Peat in Horticulture - Its use and sustainability pp 43-52.


Schuch, U., Redak, R. A., Bethke, J., (1995). Whole plant response of six Poinsettia cultivars to three fertiliser and two irrigation regimes. Journal of the American Society of Horticultural Science 121 (1): 69-76.

Sheldon, W., (2000). Water Works. Grower Talks Jan 2000 pp 64-70.

Stanley, C. D., Harbaugh, B. K., (1989). Poinsettia irrigation based on evaporative demand and plant growth characteristics. HortScience 24 (6).

Thinggaard, K., Middlebore, A. L., (1989). Phytopthora and Pythium in pot plant culture grown on ebb and flow bench with recycling nutrient solution. Journal of Phytopathology 125: 343-352.

Tyler, H. H., Warren, S. L., Bilderback, T. E., (1996). Cyclic irrigation increases application efficiency and decreases ammonium losses. Journal of Environmental Horticulture 14 (4): 194-198.

Vegter, B., (1988). Great support for concrete glasshouse floors despite ergonomic drawbacks. Vakblad voer de Bloemiserij. 25: 30-35.

van Vliet, C., (1987). The first steps towards mechanisation of harvest processing and pot plant growing operations. Vakblad voer de Bloemiserij. 8: 58-59.

Voogt, W., Kipp, J. A., de Graaf, R., Spaans, L., (2000). A fertigation model for glasshouse crops grown in soil. In press.

Wen-fei, L. U., Weiler, T. C., Milligan, R. A., (1998). A survey on the planning and adoption of zero run-off subirrigation systems in greenhouse operations. HortScience 33 (2): 193-196.

Werkhoven, C., van Os, E. A., (1998). Measuring of the water content of greenhouse soil by TDR, FD and tensiometres. Acta Horticulturae 421: 171-177.

Wohanka, W., (1983). Plant protection in soil free cultivation systems. TASPO Magazine. No. 3, p 32-34.


Appendix I - Specification for irrigation on concrete floors

1. Dynamic loading for pot plant growing, an auction trolley with total load of 4.5 km (450 kg). Depth of concrete is usually 100 mm decreasing to 90 mm. The reinforcement consists of structural steel mats of 6 mm diameter mesh, width 150-200 mm.

2. Distribution pipe for watering and heating must not form an obstacle to transport and take up some of the room intended for plants.

3. Uniform heat output to give uniform plant growth, with 3% maximum difference in temperature.

4. Maximum water flow temperature 50oC.

5. Heat output must be capable of being matched to the plant needs and there must be a safety device to prevent too high a root temperature. The heating coil should be either 16 mm or 20 mm diameter. With 75 m plus coil, 20-25 mm pipe should be used and separation between lengths should be no more than 25 cm. This ensures that the temperature gradients are no more than 2oC. All piping should be anchored to the mesh reinforcement.

6. The water supply to a floor must be as uniform as possible with a maximum difference in depth for immersion of up to 10 mm.

7. After watering, no pools must remain on the floor.

8. Watering pipes must not become blocked.

9. Water absorption by the floor must be as low as possible, because of the possibility of nutrient solution attacking the concrete. A pH of 5.5-6 is common and sometimes lower.

10. A low water absorption is also desirable to prevent too much evaporation which costs energy and leads to high humidity in and around the crop as well as in the glasshouse.

11. The floor must be easy to clean after use.

12. The concrete must be durable and require little maintenance.


Appendix II - Stage 1 irrigation test results

Nursery System Media Area tested (m2)

No. pots

Spacing /m2

Quantity water

applied (l)

Weight before irrig (g)

Weight after

irrig (g)

Water uptake per plant (ml)

Quantity water applied/plant

(ml)

Recirculated water/plant

(ml)

Unused water

/plant (ml)Ebb A Ebb/flood benches Bulrush Poinsettia mix

with extra perlite7.02 90 13 160 463 545 82 1778 1696 0

Ebb B Ebb/flood bench Lithuanian + Bulrush mix

6.92 105 15 142.4 411 536 125 1356 1231 0

Ebb C Ebb/flood bench Klausmann 10 200 20 231 513 652 139 1155 1016 0Ebb/cap D

Cap-mat on bench 24.48 300 12 605 442 582 140 2017 1877 0

Cap A1 Cap-mat on floor Own mix Shamrock/perlite

134.75 1875 14 151.6 547 584 37 81 0 44

Cap A2 Cap-mat on bench Own mix Shamrock/perlite

8.85 95 11 24 528 606 78 253 0 175

Cap B1 Cap-mat on bench Sinclair Poinsettia mix 120 1848 15 321.6 537 568 31 174 0 143Cap B2 Cap-mat on floor Sinclair Poinsettia mix 929.6 18788 20 11827.2 353 425 72 630 0 558Cap C Drip hose on matting Bulrush Poinsettia mix 64 528 8 88.8 510 539 29 168 0 139Cap D Tape on saucers 88.94 756 9 194.6 574 615 41 257 0 216Cap E Gantry on cap Bulrush 54 540 10 253 501 583 82 469 0 54Tric A1 Trickle Peat/perlite 272 3000 11 603 544 650 106 201 0 95Tric A2 Trickle Peat/perlite 272 3000 11 570 465 635 170 190 0 20Tric B Trickle 441 4410 10 671.2 514 614 100 152 0 52Tric C Trickle Levington MC2 +

20%Coarse2500 10000 4 800 575 633 58 80 0 22

Trough A Trough track Sinclair+perlite 58.8 544 9 926.5 373 591 218 1703 0 1485Hand A Hand-watering Sinclair Poinsettia mix 31.7 330 10 114 516 641 125 345 0 220Hand B Hand-watering Bulrush Poinsettia 32 604 19 140 466 679 213 232 0 19Hand C Hand-watering Bulrush Poinsettia mix 10 70 7 54.89 643 814 171 784 0 613Hand D Hand-watering onto

saucers42.86 450 10 253.7 525 697 172 564 0 392

Spray A Overhead sprayline boom

Bulrush 6 117 20 33.696 352 481 129 288 0 159


Appendix III - Water Quality for Stage 1 Nurseries (Untreated water)

Nursery pH EC NH4 NO3 P K Ca Mg Na Cl SO4 Fe Mn Cu Zn B Alk KCa KMg KNLogdate æS/cm

20øCmg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l Mg/l mg/l Mg/l mg/l

Trough A 28/09/99 7.4 367 < 1 5 < 1 2 56.4 6 17 31 18 < 0.10 0.01 < 0.01 0.02 < 0.10 102 0 0.4 0.5

Ebb A 27/09/99 7.7 640 < 1 7 < 1 4 136 4 11 35 < 10 < 0.10 < 0.01 0.01 0.01 < 0.10 337 0 1 0.5Ebb B 28/09/99 6.9 567 < 1 49 < 1 1 104 2 12 24 < 10 < 0.10 < 0.01 < 0.01 0.01 < 0.10 68 0 0.6 0Ebb C 30/11/99 7.3 1010 <1 54 <1 22 114 24 41 72 48 <0.10 0.02 <0.01 0.01 0.1 0.2 0.9 0.4

Cap A1 24/09/99 8 460 < 1 < 1 < 1 < 1 83.5 6 11 24 28 < 0.10 < 0.01 < 0.01 0.02 < 0.10 166 0 0.1 < 1.0Cap A2 24/09/99 8 580 < 1 < 1 < 1 < 1 113 8 13 29 37 < 0.10 0.04 < 0.01 1.26 < 0.10 229 0 0.1 < 1.0Cap B 24/09/99 8 530 < 1 3 < 1 3 90 6 17 37 19 < 0.10 < 0.01 < 0.01 0.11 < 0.10 200 0 0.5 1Cap C 23/09/99 7.9 540 < 1 8 < 1 < 1 108 6 11 27 13 < 0.10 < 0.01 0.04 0.1 < 0.10 239 0 < 0.0 < 0.1Ebb/cap D - borehole

09/12/99 7 670 <1 36 <1 2 85.5 17 27 42 17 <0.10 0.01 <0.01 0.16 <0.10 146 0 0.1 0.1

Ebb/cap D - mains

09/12/99 6.8 480 <1 10 <1 2 55.8 14 26 49 19 <0.10 0.02 0.22 0.3 0.12 127 0 0.1 0.1

Tric A 23/09/99 8 700 < 1 5 < 1 6 70.8 15 65 89 31 < 0.10 < 0.01 < 0.01 0.03 0.17 176 0.1 0.4 1.4Tric B 05/10/99 7.6 250 < 1 < 1 < 1 1 21.2 4 26 11 21 < 0.10 0.02 0.01 <

0.01< 0.10 73 0.1 0.2 1

Tric C 05/10/99 7.8 470 < 1 < 1 < 1 4 74.5 16 16 14 < 10 0.2 0.55 < 0.01 < 0.01

< 0.10 298 0.1 0.3 4.4

Hand A 28/09/99 7.7 863 < 1 10 < 1 4 152 9 43 76 33 < 0.10 0.01 < 0.01 0.15 < 0.10 317 0 0.4 0.4Hand B 03/09/99 7.5 440 < 1 22 < 1 6 64.1 8 17 31 23 2.28 < 0.01 < 0.01 0.01 < 0.10 146 0.1 0.7 0.3Hand C 23/09/99 7.9 680 < 1 10 3 12 92.8 10 46 57 24 < 0.10 < 0.01 0.02 0.02 0.3 224 0.1 1.2 1.2


Appendix IV - Water Quality in Stage 1 Nurseries (Irrigation water - including feed where added)



Trough A 28/09/99 6.9 1770 70 173 25 169 83.7 20 30 31 22 1.54 0.75 0.74 0.35 0.39 107 2 8.6 0.7

Ebb A 27/09/99 7.1 1520 8 142 24 144 191 19 17 39 11 0.67 0.3 0.33 0.25 0.3 229 0.8 7.5 1Ebb B 28/09/99 6 1750 16 185 35 217 115 37 54 26 29 6.9 3.41 3.14 1.31 1.51 39 1.9 5.9 1.1Ebb C 05/10/99 6.1 2480 80 173 77 333 118 53 49 83 126 1.05 0.61 0.18 0.64 0.26 68 2.8 6.3 1.3

Cap A1 24/09/99 7 1720 9 168 35 151 241 8 13 29 32 < 0.10 < 0.01 < 0.01 0.12 < 0.10 137 0.6 17.9 0.9Cap B 24/09/99 6.7 1170 12 137 17 185 102 1 6 10 < 10 0.23 0.06 0.12 0.13 < 0.10 44 1.8 231 1.2Cap C 23/09/99 6.7 1840 13 160 40 211 212 11 15 30 32 0.54 3.49 0.37 0.4 0.23 185 1 18.5 1.2Ebb/cap D 08/10/99 6.9 1740 35 164 49 178 99 49 35 41 18 1.31 0.67 0.7 0.79 0.39 142 1.8 3.6 0.9Cap E 23/09/99 6.9 900 4 35 6 40 78.1 18 60 85 30 0.28 0.11 0.03 0.08 0.22 161 0.5 2.2 1

Tric A1 + feed

23/09/99 7.1 710 < 1 38 < 1 4 70.6 15 56 77 27 < 0.10 < 0.01 < 0.01 0.45 0.15 29 0.1 0.3 0.1

Tric A2 - feed

23/09/99 6.9 1270 10 77 24 150 69.1 21 58 80 37 < 0.10 0.04 0.02 0.06 0.16 93 2.2 7.2 1.7

Tric B 05/10/99 6.6 1280 77 111 19 119 23.2 13 24 10 30 1.64 0.05 0.01 0.05 0.44 54 5.2 8.9 0.6Tric C + feed

05/10/99 5.2 1170 12 130 12 82 108 27 16 14 < 10 0.75 1.23 0.08 0.27 0.16 29 0.8 3.1 0.6

Tric C - feed

05/10/99 5.8 690 1 64 4 12 87.7 19 16 14 < 10 0.1 1.26 0.02 0.1 < 0.10 49 0.1 0.7 0.2

Hand A 28/09/99 7.3 1670 11 75 40 242 151 22 44 78 57 < 0.10 0.05 0.02 0.06 < 0.10 312 1.6 10.8 2.8Hand B 27/09/99 6.9 2110 112 150 63 148 71 47 42 31 83 4.01 1.6 1.52 0.63 0.9 181 2.1 3.2 0.6Hand C 23/09/99 7 1960 11 189 36 173 234 20 61 64 31 2.6 1.23 1 0.42 0.86 185 0.7 8.7 0.9


Appendix V - Water Quality of Nurseries in Stage 1 (Run-off water)



Trough A 28/09/99 6.8 2280 81 232 37 236 77.2 27 35 31 24 2.21 0.84 1.09 0.47 0.58 112 3.1 8.9 0.8

Ebb B 28/09/99 6.1 1720 14 180 34 210 113 36 53 26 29 6.7 3.33 3.04 1.26 1.48 45 1.9 5.9 1.1Ebb C 05/10/99 5.9 2470 67 176 77 332 119 53 49 83 126 1.05 0.6 0.18 0.64 0.26 54 2.8 6.3 1.4

Cap A 24/09/99 7.7 730 2 18 8 29 111 16 16 40 45 < 0.10 < 0.01 < 0.01 0.07 < 0.10 181 0.3 1.8 1.4Cap B 24/09/99 6.6 2050 21 234 26 211 139 7 12 20 14 3.61 0.03 0.01 0.47 < 0.10 54 1.5 31.6 0.8Cap C 23/09/99 7.4 1650 < 1 131 2 46 200 67 44 93 33 < 0.10 0.04 0.02 0.08 < 0.10 0.2 0.7 0.4Ebb/cap D 08/10/99 7 1770 30 167 53 196 113 50 39 43 20 1.47 0.82 0.86 0.97 0.44 142 1.7 3.9 1

Hand A 28/09/99 7.6 1610 11 67 32 210 156 21 49 87 57 < 0.10 0.03 0.02 0.1 < 0.10 332 1.4 10 2.7Hand B 27/09/99 7.2 2550 139 181 68 183 102 68 55 49 111 5.59 1.92 1.62 0.81 0.91 239 1.8 2.7 0.6Hand C 23/09/99 6.4 2990 13 332 43 248 254 88 126 129 66 4.05 0.48 0.72 0.87 0.96 73 1 2.8 0.7


Appendix VI - Average Particle Size Analysis results (% of particles) and AFPs for Stage 1 nurseries tested

Nursery 13.2mm 9.5mm 6.7mm 4.8mm 3.4mm 2.0mm 1.0mm 0.5mm 0.1mm Pan AFP (%)

Cap D/ Hand D 19.1 20.8 11.4 11.4 8.6 10.1 7.9 6.2 3.4 1.2 7.6%Hand C 11.2 11.6 8.2 9.2 7.8 9.8 10.7 12.8 15.9 2.7 5.5%Tric C 11.2 11.6 8.2 9.2 7.8 9.8 10.7 12.8 15.9 2.7 4.0%Cap B1/B2 27.2 19.2 2.3 1.1 6.7 8.0 11.6 15.1 8.6 0.2 5.5%Cap C 11.4 21.8 12.4 11.9 9.3 9.4 8.3 7.6 7.0 0.9 3.4%Ebb A 7.7 11.5 14.0 13.6 11.0 11.0 9.9 9.0 10.1 2.1 4.7%Trough A 19.8 14.7 8.8 8.5 9.7 10.5 14.4 8.9 4.4 0.4 10.3%Ebb B 13.2 12.9 5.6 9.0 8.9 12.5 16.8 11.9 9.3 0.7 7.9%Hand A 21.0 20.5 11.0 9.4 13.2 9.9 6.7 5.7 2.4 0.2 9.0%Cap A1/A2 13.1 22.8 10.9 10.9 10.1 10.5 8.8 8.2 3.8 0.9 3.4%

Average Particle Size Analysis results (% of particles) and AFPs for Stage 2 nurseries tested

Nursery Samples taken

13.2mm 9.5mm 6.7mm 4.8mm 3.4mm 2.0mm 1.0mm 0.5mm 0.1mm Pan AFP (%)

A Start 26.8 21.4 10.0 9.9 9.5 8.7 5.4 4.8 3.3 0.3 7.2%End 20.9 14.5 9.5 9.2 11.6 12.3 10.9 7.3 3.7 0.2 10.0

B Start 12.7 13.4 9.8 10.8 9.4 11.4 10.4 9.3 10.1 2.8 4.5%End 13.8 16.5 12.8 9.9 11.2 12.2 9.2 7.9 5.4 1.2 8.1

C Start 8.1 13.9 13.1 14.0 10.6 9.7 9.7 9.1 10.4 1.3 8.7%End 13.7 21.7 15.8 8.6 6.7 7.0 7.2 8.4 9.5 1.4 9.9

D Start 10.8 13.3 11.7 14.4 9.6 10.5 10.1 9.1 7.9 2.6 7.9%End 12.9 16.3 9.2 11.1 9.6 10.6 9.8 9.3 9.5 1.8 9.8

Note: ‘Start’ refers to samples taken soon after potting (August) and ‘End’ refers to samples taken at point of sale (December).


Appendix VII - Quantity of water applied in each nursery to each plant in Stage 2

Date Cumulative water application per plant (ml)

A B C D01-Aug02-Aug03-Aug 300

04/08/99 60005/08/99 65006/08/99 1929 70007/08/99 1929 71008/08/99 1929 72009/08/99 1929 72010/08/99 114 1929 72011/08/99 114 2748 72012/08/99 227 2748 27 73013/08/99 341 2748 27 75014/08/99 455 2748 27 75015/08/99 455 3681 76 80016/08/99 568 3681 113 81017/08/99 568 4403 113 82018/08/99 682 4403 113 83019/08/99 682 4403 169 85020/08/99 795 4403 210 90021/08/99 795 5197 210 93022/08/99 795 5197 262 96023/08/99 795 5197 262 100024/08/99 909 5197 295 117025/08/99 909 5197 349 120026/08/99 1023 5197 349 125027/08/99 1136 5197 349 130028/08/99 1136 5892 349 135029/08/99 1136 5892 383 140030/08/99 1250 5892 383 145031/08/99 1364 5892 383 155001/09/99 1477 5892 432 158002/09/99 1591 6544 487 160003/09/99 1591 6544 487 163004/09/99 1705 6544 526 165005/09/99 1705 6544 526 168006/09/99 1705 6544 573 170007/09/99 1818 6544 573 172008/09/99 1932 6544 632 193009/09/99 1932 8748 680 200010/09/99 1932 8748 736 210011/09/99 1932 8748 736 215012/09/99 1932 8748 736 221013/09/99 3082 10831 736 226014/09/99 3082 10831 798 232015/09/99 3082 10831 849 2320



A B C D16/09/99 4232 10831 849 232017/09/99 4232 12958 849 267218/09/99 4232 12958 872 267219/09/99 5382 12958 872 281120/09/99 6532 12958 872 281121/09/99 6532 15041 887 292422/09/99 7682 15041 887 292423/09/99 7682 15041 887 315624/09/99 8832 15041 887 335425/09/99 8832 16741 887 335426/09/99 9982 16741 917 356927/09/99 9982 16741 917 356928/09/99 11132 16741 917 356929/09/99 12282 16741 917 356930/09/99 12282 18674 917 356901/10/99 13432 18674 917 356902/10/99 14582 20838 1014 356903/10/99 15732 20838 1014 356904/10/99 16882 20838 1014 375205/10/99 16882 20838 1014 385106/10/99 19182 22984 1014 385107/10/99 21482 22984 1014 439708/10/99 23782 22984 1014 439709/10/99 26082 22984 1014 439710/10/99 26082 25294 2132 439711/10/99 28382 25294 2132 439712/10/99 30682 25614 2132 499313/10/99 30682 25614 2132 499314/10/99 30682 26238 3095 499315/10/99 32982 26238 3095 499316/10/99 32982 26238 3282 507617/10/99 32982 26238 3282 507618/10/99 32982 26801 3282 507619/10/99 32982 26801 3653 515920/10/99 32982 26801 3653 515921/10/99 35282 26801 3653 515922/10/99 35282 27378 3653 515923/10/99 35282 27378 3653 515924/10/99 35282 27378 3653 515925/10/99 35282 28481 3653 539126/10/99 35282 28481 3653 539127/10/99 37582 28481 3653 539128/10/99 37582 30804 3653 539129/10/99 37582 30804 3653 552330/10/99 39882 31154 3653 552331/10/99 39882 31154 3653 5523



A B C D01/11/99 42182 31154 3653 552302/11/99 42182 31154 3653 582103/11/99 42182 31154 4195 582104/11/99 42182 31154 4195 582105/11/99 44482 31414 4875 619306/11/99 44482 31414 4875 619307/11/99 46782 31414 4875 619308/11/99 46782 31558 5065 619309/11/99 46782 31558 5065 656510/11/99 49082 31558 5493 656511/11/99 49082 31558 5493 656512/11/99 51682 31558 5743 656513/11/99 51682 31558 5743 656514/11/99 51682 31558 5743 656515/11/99 51682 31558 5991 656516/11/99 51682 33128 5991 689617/11/99 51682 33128 6249 689618/11/99 53982 33128 6249 689619/11/99 53982 33128 6665 735020/11/99 53982 33128 6665 735021/11/99 53982 33128 6665 735022/11/99 53982 33128 6665 784623/11/99 56282 35094 6665 784624/11/99 56282 35094 6871 784625/11/99 56282 35094 6871 784626/11/99 56282 35094 6871 825927/11/99 56282 35094 7549 825928/11/99 58582 35094 7549 825929/11/99 58582 35094 7549 825930/11/99 58582 39248 7549 825901/12/99 60882 39248 7549 825902/12/99 60882 39248 7549 896203/12/99 60882 39248 7549 896204/12/99 60882 42371 7549 896205/12/99 63482 42371 7549 896206/12/99 63482 42371 937507/12/99 65782 42371 937508/12/99 9375


Appendix VIII - Profile of water use on each nursery

Quantity and frequency of water application per plant - Nursery A

0

500

1000

1500

2000

2500

3000

3500

4000

450001

-Aug

06/0

8/99

11/0

8/99

16/0

8/99

21/0

8/99

26/0

8/99

31/0

8/99

05/0

9/99

10/0

9/99

15/0

9/99

20/0

9/99

25/0

9/99

30/0

9/99

05/1

0/99

10/1

0/99

15/1

0/99

20/1

0/99

25/1

0/99

30/1

0/99

04/1

1/99

09/1

1/99

14/1

1/99

19/1

1/99

24/1

1/99

29/1

1/99

04/1

2/99

09/1

2/99

Date

ml w

ater

Quantity and frequency of water application per plant - Nursery B

0

500

1000

1500

2000

2500

3000

3500

4000

4500

01-A

ug

06/0

8/99

11/0

8/99

16/0

8/99

21/0

8/99

26/0

8/99

31/0

8/99

05/0

9/99

10/0

9/99

15/0

9/99

20/0

9/99

25/0

9/99

30/0

9/99

05/1

0/99

10/1

0/99

15/1

0/99

20/1

0/99

25/1

0/99

30/1

0/99

04/1

1/99

09/1

1/99

14/1

1/99

19/1

1/99

24/1

1/99

29/1

1/99

04/1

2/99

09/1

2/99

Date

ml w

ater

Quantity and frequency of water application per plant - Nursery C

0

500

1000

1500

2000

2500

3000

3500

4000

4500

01-A

ug

06/0

8/99

11/0

8/99

16/0

8/99

21/0

8/99

26/0

8/99

31/0

8/99

05/0

9/99

10/0

9/99

15/0

9/99

20/0

9/99

25/0

9/99

30/0

9/99

05/1

0/99

10/1

0/99

15/1

0/99

20/1

0/99

25/1

0/99

30/1

0/99

04/1

1/99

09/1

1/99

14/1

1/99

19/1

1/99

24/1

1/99

29/1

1/99

04/1

2/99

09/1

2/99

Date

ml w

ater


Quantity and frequency of water application per plant - Nursery D

0

500

1000

1500

2000

2500

3000

3500

4000

4500

01-A

ug

06/0

8/99

11/0

8/99

16/0

8/99

21/0

8/99

26/0

8/99

31/0

8/99

05/0

9/99

10/0

9/99

15/0

9/99

20/0

9/99

25/0

9/99

30/0

9/99

05/1

0/99

10/1

0/99

15/1

0/99

20/1

0/99

25/1

0/99

30/1

0/99

04/1

1/99

09/1

1/99

14/1

1/99

19/1

1/99

24/1

1/99

29/1

1/99

04/1

2/99

09/1

2/99

Date

ml w

ater


Appendix IX - Light Levels Reaching Stage 2 Nurseries (W/m2)

Nursery A Nursery BDay Aug Sep Oct Nov Aug Sep Oct Nov Dec

1 6080 4237 1006 484 7017 4540 2077 362 9572 5944 4693 2969 1818 4451 5344 3516 1863 13353 5363 5290 2644 823 4720 5604 3340 1533 4804 4868 4342 2966 1332 3324 5347 3827 1679 13445 5335 4670 3567 272 7045 5067 3754 260 12506 6330 3836 3330 1774 3274 5166 3555 1840 4447 1145 3253 1131 1737 6489 4052 1693 1315 8698 1270 3489 1829 1059 4796 4394 1380 754 3269 795 4323 1184 1062 3765 5185 1519 1838 792

10 1523 2599 2099 1101 2481 4468 1457 588 105511 4042 3934 2699 559 3829 4293 2939 1744 18312 3033 2627 2480 170 6568 4451 3527 1567 86313 2424 1846 2524 659 3989 3071 3307 1962 35714 1426 681 2221 548 4174 1003 2988 738 126015 4392 878 806 887 4555 2671 2770 1890 127816 3472 1715 1929 1140 4901 1988 2950 1723 111717 3127 3989 2544 1156 1901 4023 3097 1807 19518 2866 2886 2819 1462 5078 1706 3303 1360 34119 2513 1309 2416 792 5710 2263 2969 1507 136620 2741 1068 512 648 5973 1631 425 1421 110421 3519 1940 181 876 5593 4061 449 811 12422 4804 2321 948 259 4814 1913 914 446 16023 4392 2213 1357 678 4976 2905 1909 778 109524 2199 1198 664 659 1179 2733 1068 1033 22025 2694 2382 1882 945 2202 2956 2922 652 55026 3700 2282 1601 945 5712 3842 2342 849 54327 3500 2027 1915 787 4774 2518 2438 1360 34328 4912 2257 1690 1095 5989 2630 1356 921 106729 4598 1487 1337 728 5099 1794 787 147 121630 4551 1977 1095 153 5283 2907 1094 902 18131 3367 1988 3934 2329 399


Nursery C Nursery DDay Aug Sep Oct Nov Dec Aug Sep Oct Nov Dec

1 5587 5007 1276 - 988 5262 3275 701 408 8662 4797 5095 3113 2080 886 4602 3350 2471 1787 3663 1554 4636 2061 1392 614 1786 3372 1980 1020 5204 4472 4916 3568 1119 1095 4594 4603 3295 427 4475 5887 5056 3276 339 916 3106 4865 2994 291 4916 3732 4298 2967 1556 363 4803 4462 2990 1814 907 1707 3479 915 1076 561 1449 3567 1469 557 6408 628 2551 1335 637 274 2177 2671 875 485 2759 2852 4768 1766 1526 887 1271 4831 696 1384 156

10 1890 4891 1202 555 763 2510 4940 968 849 52911 4187 3175 3276 647 242 3834 1622 2208 318 11212 2570 3356 2410 1231 197 3389 3867 1990 505 30813 2871 3393 2776 564 155 2026 3149 2696 284 26014 4634 2052 2667 499 1065 2920 4332 662 354 71015 5068 681 1943 1257 530 3345 3144 1184 544 71116 - 2911 1727 912 756 3546 1876 2020 789 45517 - 4417 2809 1498 235 2172 3702 2677 1361 38718 - 1784 2965 1462 661 3319 2343 2850 781 51919 1866 1002 2761 1274 1141 1828 658 2527 1149 94920 4425 1583 1081 1213 804 3937 1988 1308 692 59421 6316 2670 429 608 141 6213 3813 420 521 21922 5091 1582 1327 434 100 6048 2516 1714 730 4423 4643 2779 1261 955 980 5289 2384 1418 570 65324 1860 2249 562 653 360 2665 2744 373 255 45725 1867 2019 1494 1116 623 1546 1990 1354 783 29726 3338 3053 1077 334 506 2977 1652 1147 145 42727 4222 1596 1805 967 510 4007 1392 1178 804 32228 5398 - 816 674 560 3857 1904 1763 230 77429 4238 - 509 249 897 2854 1120 1053 723 92230 4799 - - 530 180 2221 1403 603 349 28931 2821 - 267 1586 1266 317


Appendix X - Water Quality for Stage 2 Nurseries - Nursery A

Nursery pH EC NH4 NO3 P K Ca Mg Na Cl SO4 Fe Mn Cu Zn B Alk KCa KMg KNWeek no. Logdate æS/cm

20øCmg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l Mg/l Mg/l mg/l mg/l mg/l

A - Irrigationw34 03/09/99 7.3 930 < 1 45 < 1 18 114 23 41 73 47 < 0.10 < 0.01 < 0.01 0.02 0.1 98 0.2 0.8 0.4w36 01/10/99 4.8 2470 45 173 61 342 124 54 51 92 138 1.49 0.49 0.16 0.94 0.24 15 2.8 6.3 1.6w38 05/10/99 6.1 2480 80 173 77 333 118 53 49 83 126 1.05 0.61 0.18 0.64 0.26 68 2.8 6.3 1.3w40 09/11/99 4.9 1830 44 136 42 180 117 38 47 81 91 0.61 0.32 0.09 0.53 0.19 10 1.5 4.7 1w42w44 09/11/99 6.5 1870 52 141 42 168 116 38 46 82 81 0.65 0.34 0.1 0.6 0.19 44 1.5 4.4 0.9w46 23/11/99 6.2 1650 29 118 32 146 123 37 47 88 80 0.45 0.28 0.08 0.81 0.18 59 1.2 3.9 1

A - Run-offw34 03/09/99 7.5 1390 2 71 3 41 152 38 65 109 72 < 0.10 < 0.01 < 0.01 0.15 0.13 107 0.3 1.1 0.6w36 01/10/99 4.9 2490 50 175 63 348 126 55 52 93 141 1.5 0.49 0.17 0.96 0.24 15 2.8 6.3 1.6w38 05/10/99 5.9 2470 67 176 77 332 119 53 49 83 126 1.05 0.6 0.18 0.64 0.26 54 2.8 6.3 1.4w40 09/11/99 5 1850 42 137 41 186 121 40 48 85 94 0.61 0.31 0.1 0.62 0.2 5 1.5 4.7 1w42w44 09/11/99 6.5 1940 51 141 43 170 116 38 46 83 81 0.67 0.33 0.1 0.58 0.19 44 1.5 4.5 0.9w46 23/11/99 6.5 1350 8 86 15 84 130 37 52 94 77 0.25 0.05 0.04 0.42 0.14 68 0.7 2.3 0.9


Appendix XI - Water Quality for Stage 2 Nurseries - Nursery B


20øCmg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l Mg/l mg/l mg/l mg/l

B - Irrigationw34 25/08/99 7.2 830 2 68 < 1 3 156 3 16 29 < 10 < 0.10 < 0.01 < 0.01 0.01 < 0.10 259 0 1.2 0w36 13/09/99 7.3 1380 10 124 18 128 166 18 24 30 12 1.38 0.41 0.52 0.38 0.32 239 0.8 7.1 1w38w40 08/10/99 6.9 1740 35 164 49 178 99 49 35 41 18 1.31 0.67 0.7 0.79 0.39 142 1.8 3.6 0.9w42 25/10/99 6.8 1460 10 128 39 156 98.5 27 37 53 23 1.52 0.71 0.75 0.88 0.4 112 1.6 5.9 1.1w44 10/11/99 7 1420 9 138 23 174 121 30 33 45 18 2.15 0.27 0.3 0.56 0.21 117 1.4 5.8 1.2w46 18/11/99 6.9 1210 3 114 10 85 125 32 31 45 18 0.76 0.19 0.32 0.58 0.25 117 0.7 2.7 0.7

B - Run-offw34w36 13/09/99 7.1 1400 9 124 17 129 168 18 25 31 12 1.36 0.25 0.52 0.43 0.3 244 0.8 7.3 1w38w40 08/10/99 7 1770 30 167 53 196 113 50 39 43 20 1.47 0.82 0.86 0.97 0.44 142 1.7 3.9 1w42 25/10/99 6.9 1510 27 137 42 159 105 33 39 48 24 1.57 0.66 0.77 1.22 0.41 98 1.5 4.9 1w44 10/11/99 6.9 1530 8 141 26 188 123 33 35 47 20 2.32 0.22 0.3 0.62 0.24 112 1.5 5.7 1.3w46 18/11/99 7.1 1380 4 133 13 105 137 36 36 52 21 0.81 0.07 0.36 0.45 0.26 122 0.8 2.9 0.8


Appendix XII - Water Quality for Stage 2 Nurseries - Nursery C


20øCmg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l

C - Irrigationw34w36 09/09/99 7.2 1130 8 75 12 84 92.1 22 55 78 28 0.67 0.27 0.07 0.18 0.25 156 0.9 3.8 1w38 23/09/99 6.9 900 4 35 6 40 78.1 18 60 85 30 0.28 0.11 0.03 0.08 0.22 161 0.5 2.2 1w40 07/10/99 7.8 1370 11 155 < 1 4 235 5 18 20 15 < 0.10 0.02 < 0.01 0.02 < 0.10 93 0 0.9 0w42 25/10/99 6.6 1530 11 152 29 199 104 28 28 38 18 1.59 0.71 0.15 0.44 0.28 78 1.9 7.1 1.2w44 08/11/99 6.5 1690 9 201 21 171 180 21 18 23 13 1.02 0.49 0.11 0.26 0.2 78 1 8.2 0.8w46 18/11/99 6.6 1730 10 199 23 186 190 21 22 35 14 1.15 0.67 0.13 0.31 0.24 93 1 8.8 0.9

C - Run-offw34w36w38w40 07/10/99 7.7 1680 16 196 < 1 16 267 17 34 36 23 < 0.10 0.08 0.01 0.21 < 0.10 98 0.1 1 0.1w42w44w46


Appendix XIII - Water Quality for Stage 2 Nurseries - Nursery D


20øCmg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l Mg/l mg/l mg/l mg/l

D - Irrigationw34 03/09/99 7.1 1910 12 145 29 180 73 32 45 32 61 4.15 1.84 1.71 0.66 0.91 181 2.5 5.7 1.2w36 09/09/99 7 1780 80 137 27 148 70.2 37 38 32 66 4.37 1.56 1.43 0.55 0.76 181 2.1 4 0.7w38 27/09/99 6.9 2110 112 150 63 148 71 47 42 31 83 4.01 1.6 1.52 0.63 0.9 181 2.1 3.2 0.6w40 11/10/99 7.1 1160 45 73 19 85 62.2 23 29 32 38 2.23 0.76 0.79 0.32 0.46 171 1.4 3.7 0.7w42 20/10/99 7.1 1390 55 19 28 118 63.6 25 35 7 37 3.75 1.23 1.09 0.45 0.72 137 1.9 4.7 1.6w44 03/11/99 5.8 6600 11 773 221 529 66.2 202 51 42 35 5.26 1.5 1.71 0.58 1.12 98 8 2.6 0.7w46 17/11/99 7 1330 47 104 43 159 65.2 27 41 36 30 4.24 1.46 1.37 0.53 0.74 171 2.4 5.9 1.1

D - Run-offw34 03/09/99 6.4 2630 12 214 52 201 160 93 64 67 127 4.9 2.82 1.34 1.48 0.52 93 1.3 2.2 0.9w36 09/09/99 6.2 3150 82 289 47 240 191 114 92 101 161 8.31 2.36 1.38 1.27 0.61 93 1.3 2.1 0.7w38 27/09/99 7.2 2550 139 181 68 183 102 68 55 49 111 5.59 1.92 1.62 0.81 0.91 239 1.8 2.7 0.6w40 11/10/99 6.9 1220 40 71 19 82 78 26 32 38 49 1.94 0.32 0.7 0.34 0.41 156 1 3.2 0.7w42 20/10/99 6.4 2750 11 196 54 200 197 79 87 101 152 7 2.31 1.48 1.59 0.82 83 1 2.5 1w44 03/11/99 5.6 9230 11 1200 265 619 276 377 105 89 132 16.6 2.43 2.09 1.15 1.28 156 2.2 1.6 0.5w46

D - Untreatedw34 03/09/99 7.5 440 < 1 22 < 1 6 64.1 8 17 31 23 2.28 < 0.01 < 0.01 0.01 < 0.10 146 0.1 0.7 0.3


Appendix XIV - Nutrient content of tested plants in Stage 2 - Content of plugs at potting

Nursery Plant number

Fresh weight (g)

Dry weight (g)

Oven dry matter %

m/m

N %m/m Ca %m/m K%m/m Mg %m/m P %m/m

A 1 7.7 0.7 9.1 4.56 4.94 11.8 1.39 1.82 5 0.5 10 3.62 1.45 2.44 0.38 0.53 10.6 1.1 10.4 4 1.62 2.78 0.45 0.494 6.4 0.6 9.4 4.39 1.54 2.69 0.45 0.555 10.5 1.1 10.5 3.31 1.35 2.4 0.4 0.436 6.4 0.7 10.9 3.83 1.28 2.09 0.36 0.457 9.1 1 11 4.1 1.41 2.83 0.41 0.528 7.5 0.6 8 4.13 1.36 3.01 0.36 0.59 8.2 0.9 11 3.17 1.18 2.3 0.32 0.36

10 6.9 0.8 11.6 4.39 1.36 2.8 0.39 0.511 7.7 0.8 10.4 3.97 1.37 2.88 0.39 0.4612 4.3 0.5 11.6 4.09 1.19 2.54 0.39 0.4713 7.1 0.7 9.9 4.35 1.48 2.94 0.44 0.5214 6.9 0.8 11.6 4.52 1.46 2.96 0.41 0.5415 7.8 0.8 10.3 3.63 1.24 2.52 0.37 0.4616 6.5 0.6 9.2 4.51 1.22 2.68 0.43 0.5217 6 0.5 8.3 4.24 1.27 2.51 0.39 0.518 8.5 1 11.8 3 1.41 2.33 0.38 0.3819 5.8 0.6 10.3 3.96 1.28 2.67 0.36 0.4320 9.6 0.9 9.4 3.6 1.43 2.26 0.37 0.43

Average 7.39 0.76 10.28 3.99 1.56 3.14 0.45 0.55

B 1 7.5 0.9 12 2.73 1.53 2.14 0.33 0.32 6.9 0.9 13 2.92 1.24 1.76 0.25 0.283 5.8 0.8 13.8 2.68 1.21 1.66 0.27 0.254 8.3 0.9 10.8 2.66 1.28 1.88 0.24 0.275 4.9 0.5 10.2 2.98 1.3 2.2 0.28 0.326 4.5 0.5 11.1 2.57 0.95 1.9 0.22 0.317 7.9 0.9 11.4 2.85 1.33 2.07 0.28 0.298 4.6 0.4 8.7 3.64 1.32 2.24 0.27 0.39 4.7 0.5 10.6 3.29 1.54 2.37 0.26 0.28

10 4.4 0.4 9.1 3.56 1.6 2.63 0.3 0.3211 6.9 0.8 11.6 3 1.56 2.11 0.29 0.2912 7.4 0.8 10.8 2.71 1.31 1.86 0.31 0.2913 4.4 0.4 9.1 3.57 1.49 2.76 0.33 0.3214 5.8 0.7 12.1 2.83 1.31 2.39 0.28 0.2915 6.3 0.7 11.1 3.17 1.65 2.21 0.3 0.3116 6.6 0.7 10.6 2.89 1.37 1.93 0.27 0.2817 3.9 0.4 10.3 3.33 1.71 2.18 0.29 0.2918 5.8 0.7 12.1 3.12 1.36 1.94 0.29 0.319 4 0.4 10 3.42 1.75 2.4 0.27 0.320 5.8 0.6 10.3 2.73 1.43 2.05 0.27 0.28

Average 5.82 0.65 10.94 3.03 1.41 2.13 0.28 0.29



Fresh weight (g)

Dry weight (g)

Oven dry matter %

m/m


C 1 3.2 0.5 15.6 3.11 1.22 2.4 0.31 0.362 4.9 0.8 16.3 2.74 1.21 2.4 2.26 0.333 4.1 0.5 12.2 2.96 1.11 2.04 0.25 0.334 4.1 0.5 12.2 3.09 1.15 2.25 0.29 0.345 4.6 0.6 13 3.09 1.03 2.57 0.28 0.46 3.4 0.5 14.7 2.69 1.11 2.04 0.23 0.37 4.7 0.8 17 2.68 1.18 2.13 0.24 0.338 4.3 0.6 14 2.78 1.01 2.45 0.24 0.349 4.7 0.7 14.9 2.69 1.08 2.2 0.23 0.28

10 4.2 0.5 11.9 2.4 1.09 2.55 0.22 0.3211 3.2 0.5 15.6 1.94 1.58 2.82 0.21 0.2412 5 0.7 14 2.93 0.96 2.14 0.26 0.3613 2.9 0.2 6.9 2.98 0.9 2.4 0.26 0.3714 4.1 0.5 12.2 2.21 1.13 2.21 0.24 0.3215 5.2 0.5 9.6 2.52 1 2.12 0.26 0.316 3.9 0.5 12.8 2.69 1.12 2.15 0.27 0.3217 3.9 0.4 10.3 2.92 1.05 2.49 0.28 0.3818 5.8 0.6 10.3 3.07 1.17 2.4 0.31 0.3619 4 0.4 10 2.92 1.08 2.42 0.3 0.4420 3 0.3 10 3.14 1.3 2.49 0.3 0.38

Average 4.16 0.53 12.68 2.78 1.12 2.33 0.36 0.34

D 1 4.2 0.5 11.9 3.6 0.87 3.06 0.28 0.52 4.9 0.4 8.2 3.45 0.92 2.89 0.27 0.533 4.5 0.5 11.1 3.13 0.93 2.85 0.27 0.494 5.7 0.8 14 2.7 0.99 2.52 0.31 0.455 4 0.5 12.5 2.9 0.93 2.49 0.28 0.386 6.4 0.8 12.5 2.92 0.91 2.44 0.28 0.457 4.9 0.5 10.2 2.87 0.86 2.69 0.26 0.468 5.8 0.7 12.1 3.27 1.17 2.72 0.33 0.59 5.2 0.6 11.5 2.86 1.02 2.88 0.3 0.53

10 7.5 1 13.3 3.03 0.93 2.52 0.3 0.4211 3.2 0.4 12.5 3.41 0.85 2.97 0.26 0.4512 3.3 0.3 9.1 0.63 1.82 0.19 0.313 5.9 0.7 11.9 3.92 0.94 2.61 0.28 0.4414 4.4 0.5 11.4 3.17 0.96 3.27 0.31 0.5715 6.8 0.9 13.2 3.02 0.8 2.5 0.27 0.4216 2.4 0.3 12.5 3.54 0.42 2.11 0.15 0.3417 5.4 0.6 11.1 3.18 0.84 2.47 0.26 0.3818 5.2 0.7 12.3 3.98 0.82 2.62 0.25 0.4119 2.9 0.3 10.3 3.06 0.76 2.46 0.23 0.4220 5.6 0.7 12.5 2.82 0.7 2.38 0.24 0.36

Average 4.91 0.59 11.71 3.20 0.86 2.61 0.27 0.44


Nutrient content of tested plants in Stage 2 - Content of plants at point of sale


Fresh weight (g)

Dry weight (g)

Oven dry matter %

m/m


A 1 180.9 26.8 14.8 3.61 0.84 2.67 0.43 0.752 227.5 33.9 14.9 3.43 0.82 3.02 0.43 0.653 130.5 19.8 15.2 3.37 0.84 3.03 0.41 0.754 161.6 24.4 15.1 3.66 0.86 3.19 0.45 0.735 200.3 28.2 14.1 3.54 0.93 2.94 0.46 0.766 190.4 26.4 13.9 3.51 0.93 3.08 0.45 0.87 185.2 26.6 14.4 3.55 0.89 2.91 0.44 0.798 155.1 23.3 15 3.57 0.93 2.88 0.45 0.789 162.3 23.9 14.7 3.47 0.83 2.86 0.41 0.79

10 154.6 21.7 14 3.72 0.86 3.01 0.45 0.83Average 174.84 25.50 14.61 3.54 0.87 2.96 0.44 0.76

B 1 166.3 24.4 14.7 3.37 0.92 3.04 0.45 0.592 159.6 23.6 14.8 3.6 0.94 2.68 0.44 0.583 123.2 18 14.6 3.62 0.89 2.89 0.47 0.634 200.2 26.9 14.8 3.46 0.86 2.82 0.45 0.65 143.3 21.5 15 3.57 0.85 2.88 0.43 0.616 228.1 35.9 15.7 3.37 0.76 2.75 0.39 0.437 145.4 20.8 14.3 3.75 0.92 2.81 0.46 0.628 221.6 33.4 15.1 3.24 0.91 3.02 0.44 0.599 188.7 28.4 15.1 3.26 0.9 3 0.44 0.58

10 228.2 33.4 14.6 3.45 0.86 2.93 0.42 0.56Average 180.46 26.63 14.87 3.47 0.88 2.88 0.44 0.58

C 1 142.7 21.6 15.1 3.08 1.03 2.09 0.49 0.392 111.6 16.8 15.1 3.34 1.07 2.2 0.48 0.463 98.3 14.9 15.2 3.43 1.09 2.34 0.52 0.524 65.1 9.4 14.4 3.69 1.02 2.45 0.5 0.615 129 19.8 15.4 3.63 1 2.51 0.48 0.476 104.2 16.2 15.6 3.33 0.89 2.17 0.45 0.397 103.3 16 15.5 3.23 1 2.34 0.49 0.438 136.6 21 15.4 3.25 0.93 2.2 0.5 0.49 104.7 16.2 15.5 3.45 0.96 2.14 0.48 0.45

10 74.4 11.7 15.7 3.44 1.05 2.29 0.48 0.49Average 106.99 16.36 15.29 3.39 1.00 2.27 0.49 0.46

D 1 124 19 15.3 4.53 0.94 2.62 0.65 0.772 129.7 19 14.7 4.48 0.97 2.46 0.65 0.743 134.1 19.3 14.4 4.95 0.95 2.88 0.65 0.84 125.8 18.4 14.6 4.52 0.97 2.79 0.65 0.85 114.9 17.2 15 5.12 0.94 2.8 0.66 0.836 113.6 16 14.1 4.67 0.95 2.45 0.64 0.737 115.2 16.4 14.2 4.82 1.05 2.68 0.71 0.758 158.7 24.1 15.2 4.41 1.02 2.65 0.63 0.699 134.3 18.7 13.9 4.44 0.97 2.73 0.66 0.68

10 159.6 22.7 14.2 4.16 1.06 2.49 0.56 0.69Average 130.99 19.08 14.56 4.61 0.98 2.66 0.65 0.75


Appendix XV - Plant nutrient content and application of liquid feedNitrogenNursery Initial gN/pl PoS gN/pl Diff gN/plant applied gN/pl unused g/pl loss from system KgN unused/10,000 plants Kg unused/10,000 in systemA 0.03 0.904 0.874 2.85 1.976 0 19.76 0B 0.019 0.931 0.912 1.11 0.198 0 1.98 0C 0.015 0.555 0.54 1 0.46 0.46 4.6 4.6D 0.018 0.879 0.861 1.99 1.129 1.129 11.29 11.29PotassiumNursery Initial gK/pl PoS gK/pl Diff gK/plant applied gK/pl unused g/pl loss from system KgK unused/10,000 plants Kg unused/10,000 in systemA 0.023 0.756 0.733 9.5 8.767 0 87.67 0B 0.014 0.773 0.759 5.43 4.671 0 46.71 0C 0.012 0.371 0.359 0.2 -0.159 -0.159 -1.59 -1.59D 0.015 0.507 0.492 1.69 1.198 1.198 11.98 11.98PhosphorusNursery Initial gP/pl PoS gP/pl Diff gP/plant applied gP/pl unused or

recirculatedg/pl loss from system KgP unused/10,000 plants Kg unused/10,000 in system

A 0.004 0.194 0.19 2.35 2.16 0 21.6 0B 0.002 0.156 0.154 1.08 0.926 0 9.26 0C 0.002 0.075 0.073 0.29 0.217 0.217 2.17 2.17D 0.003 0.143 0.14 0.38 0.24 0.24 2.4 2.4MagnesiumNursery Initial gMg/pl PoS gMg/pl Diff gMg/plant applied gMg/pl unused g/pl loss from system KgMg unused/10,000 plants Kg unused/10,000 in systemA 0.003 0.112 0.109 0.92 0.811 0 8.11 0B 0.002 0.118 0.116 0.5 0.384 0 3.84 0C 0.002 0.08 0.078D 0.002 0.124 0.122 0.27 0.148 0.148 1.48 1.48

PoS g/pl = content of plant at Point of SaleInitial g/pl = content of plant at pottingg/plant applied = quantity applied to each plant through the season (may have been applied more than once in recirculating systems (i.e. Nsy A and B)g/plant unused = difference between quantity applied and quantity taken up by plantg/plant loss from system = takes into account recirculation


Appendix XVI - Leaf tissue analysis

Nursery Date Cl N P K Mg Ca Mn Cu Zn Mo B% % % % % % mg/kg mg/kg mg/kg mg/kg mg/kg

A 25/11/99 0.8 5.5 0.9 3.0 0.7 1.1 80.5 3.4 28.8 0.4 18.311/11/99 0.7 6.5 0.8 2.4 0.6 0.9 65.5 4.4 28.2 0.1 16.0

1.0 6.8 1.1 3.9 1.3 2.3 124.6 9.1 57.4 0.5 20.309/10/99 1.2 5.0 0.9 2.9 1.2 2.6 125.5 3.6 49.3 0.5 16.901/10/99 1.1 4.8 0.9 3.1 1.0 2.6 113.5 3.8 57.4 0.8 21.907/09/99 1.1 5.7 0.8 2.3 0.9 2.3 107.9 2.9 60.4 0.5 15.9

B 22/11/99 0.3 5.7 0.7 2.5 0.6 0.9 56.1 5.4 54.6 5.5 20.209/11/99 0.3 5.7 0.8 2.8 0.6 0.8 51.8 4.8 47.9 6.2 19.627/10/99 0.4 5.6 0.7 3.5 0.6 0.9 54.3 3.6 36.6 7.3 17.515/10/99 0.4 5.0 0.6 3.4 0.5 0.9 54.2 3.0 25.3 8.9 18.416/09/99 0.0 4.4 0.8 3.2 0.6 1.3 112.1 4.2 38.1 0.8 18.0

C 07/12/99 0.6 5.1 0.5 2.3 0.8 1.3 115.6 2.5 25.0 0.7 20.617/11/99 0.0 5.6 0.6 2.4 0.9 1.4 129.3 2.8 29.2 0.9 16.827/10/99 0.7 5.2 0.6 3.0 0.8 1.2 109.1 3.0 27.6 0.8 19.630/09/99 1.0 0.0 5.6 0.7 2.2 0.8 1.4 131.2 52.1 0.8 21.916/09/99 5.8 1.0 2.9 0.6 0.8 96.0 3.0 52.0 0.8 28.2


% Nitrogen in leaf tissue

0

1

2

3

4

5

6

7

36-37 38-39 40-41 42-43 44-45 46-47 48-49

Week number

% N

itrog

en % Nitrogen A

% Nitrogen B

% Nitrogen C


Appendix XVII - Chart to show Average pH of irrigation and run-off water in Stage 2 nurseries

Average pH of irrigation and run-off water at each nursery in Stage 2

0

1

2

3

4

5

6

7

8

A B C D

Nursery

pH

IrrigationRun-off


Appendix XVIII - Mean sieve analysis and AFP results for Stage 2 nurseries

Nursery Sample taken

13.2mm 9.5mm 6.7mm 4.8mm 3.4mm 2.0mm 1.0mm 0.5mm 0.1mm Pan AFP (%)

A Start 26.8 21.4 10.0 9.9 9.5 8.7 5.4 4.8 3.3 0.3 7.2%End 20.9 14.5 9.5 9.2 11.6 12.3 10.9 7.3 3.7 0.2 10.0

B Start 12.7 13.4 9.8 10.8 9.4 11.4 10.4 9.3 10.1 2.8 4.5%End 13.8 16.5 12.8 9.9 11.2 12.2 9.2 7.9 5.4 1.2 8.1

C Start 8.1 13.9 13.1 14.0 10.6 9.7 9.7 9.1 10.4 1.3 8.7%End 13.7 21.7 15.8 8.6 6.7 7.0 7.2 8.4 9.5 1.4 9.9

D Start 10.8 13.3 11.7 14.4 9.6 10.5 10.1 9.1 7.9 2.6 7.9%End 12.9 16.3 9.2 11.1 9.6 10.6 9.8 9.3 9.5 1.8 9.8


Changes in AFP between the start and end of the season on Stage nurseries

0

1

2

3

4

5

6

7

8

9

10

A B C D

Nursery

% A

FP Start

End


Percentage particles <2mm and AFPs at start and end of season for each system

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

Star

tA En

d

Star

tB En

d

Star

tC En

d

Star

tD En

d

Nursery and time of sample

% A

FP a

nd %

par

ticle

s <

2mm

Percentage <2mm

AFP (%)


Appendix XIX - Plant quality scoring for Stage 2 plants

Nursery Average Average Stage ofVariety Rep Plant Date of Height Spread Primary Secondary Total Star size Cyathia Cyathia Grassy Sleevability Plant

record (cm) (cm) Breaks Breaks Breaks Class Size Development Growth Quality(auto) (1 - 4) (1,2,3) (1 - 6) (0, 1, 3) (1, 3, 5) (0,1,2)

A sonora 1 1 29th Nov 99 31 47 3 4 7 25 1 1 0 5 1 sonora 1 2 27 46 5 4 9 24 1 2 2 5 2 sonora 1 3 22 38 5 3 8 17 1 2 1 5 1 sonora 1 4 28 48 5 3 8 22 1 3 0 5 2 sonora 1 5 25 43 7 1 8 21 1 1 0 5 2 sonora 1 6 29 42 5 4 9 23 1 2 0 5 2 sonora 1 7 26 40 6 1 7 24 1 1 0 5 2 sonora 1 8 27 31 2 7 9 28 1 1 0 5 1 sonora 1 9 26 39 3 5 8 25 1 2 0 5 2 sonora 1 10 27 41 5 1 6 26 1 1 0 5 2 sonora 2 1 29 40 6 0 6 27 1 2 2 5 2 sonora 2 2 24 45 5 4 9 24 1 2 1 5 2 sonora 2 3 24 39 4 3 7 24 1 2 0 5 2 sonora 2 4 28 43 5 3 8 22 1 2 0 5 2 sonora 2 5 24 42 5 1 6 22 1 2 0 5 2 sonora 2 6 26 41 4 3 7 21 1 2 0 5 2 sonora 2 7 26 42 5 2 7 21 1 1 0 5 2 sonora 2 8 23 42 7 1 8 21 1 1 0 5 2 sonora 2 9 28 42 4 5 9 20 1 1 0 5 1 sonora 2 10 27 46 4 1 5 28 1 1 0 5 2




B sonora 1 1 8th Dec 99 28 40 5 2 7 23 1 2 2 5 2 sonora 1 2 30 41 3 3 6 25 2 2 1 5 1 sonora 1 3 25 38 2 3 5 24 1 2 1 5 1 sonora 1 4 27 42 5 3 8 26 2 4 2 5 2 sonora 1 5 28 40 4 3 7 21 1 3 2 5 2 sonora 1 6 30 40 4 2 6 27 2 3 2 5 2 sonora 1 7 30 41 2 3 5 24 1 2 3 5 1 sonora 1 8 30 44 4 3 7 23 2 2 2 5 2 sonora 1 9 28 47 5 1 6 21 2 3 2 5 2 sonora 1 10 29 44 6 1 7 27 2 4 3 3 2 sonora 2 1 32 43 4 3 7 27 1 2 3 5 2 sonora 2 2 22 39 5 1 6 18 1 2 3 5 2 sonora 2 3 25 47 5 2 7 23 1 2 0 5 2 sonora 2 4 24 48 5 1 6 19 1 2 3 5 2 sonora 2 5 30 44 4 3 7 24 1 2 3 5 2 sonora 2 6 26 39 5 0 5 24 1 2 3 5 2 sonora 2 7 32 47 4 4 8 29 2 3 0 5 2 sonora 2 8 29 43 5 1 6 21 1 2 3 5 2 sonora 2 9 31 39 3 4 7 26 1 4 3 5 1 sonora 2 10 32 41 5 2 7 25 2 4 2 5 2




C sonora 1 1 20th Nov 99 30 40 4 3 7 25 1 2 0 5 2 sonora 1 2 24 38 3 4 7 21 1 1 0 5 1 sonora 1 3 26 40 3 2 5 21 1 2 0 5 1 sonora 1 4 21 47 4 1 5 24 1 1 0 5 1 sonora 1 5 24 39 6 0 6 22 1 1 0 5 2 sonora 1 6 27 40 3 3 6 27 1 1 0 5 1 sonora 1 7 27 45 4 1 5 27 1 2 0 5 2 sonora 1 8 27 47 4 2 6 27 1 3 0 5 2 sonora 1 9 24 42 5 0 5 27 1 1 0 5 2 sonora 1 10 26 36 3 3 6 27 1 2 0 5 1 sonora 2 1 28 45 5 1 6 25 1 1 0 5 2 sonora 2 2 28 43 4 1 5 28 1 2 0 5 1 sonora 2 3 25 41 5 2 7 26 1 1 0 5 2 sonora 2 4 16 43 5 1 6 21 1 1 0 5 1 sonora 2 5 23 43 5 1 6 23 1 2 0 5 2 sonora 2 6 21 42 5 0 5 22 1 2 0 5 2 sonora 2 7 27 38 5 1 6 23 1 1 0 5 2 sonora 2 8 25 40 4 2 6 27 1 2 0 5 2 sonora 2 9 25 42 5 1 6 26 1 1 0 5 2 sonora 2 10 29 42 5 1 6 28 1 2 0 5 2




D Malibu 1 1 10th Dec 99 25 39 5 1 6 24 1 2 0 5 2 Malibu 1 2 22 42 6 1 7 23 1 2 0 5 2 Malibu 1 3 27 43 3 5 8 23 1 1 0 5 2 Malibu 1 4 23 40 4 2 6 25 1 2 0 5 1 Malibu 1 5 23 37 5 2 7 18 1 1 0 5 1 Malibu 1 6 22 36 4 2 6 21 1 2 0 5 1 Malibu 1 7 24 41 5 0 5 19 1 1 0 5 1 Malibu 1 8 27 50 6 2 8 23 2 2 0 4 2 Malibu 1 9 22 45 5 1 6 25 1 2 0 5 2 Malibu 1 10 28 47 5 0 5 26 1 1 0 5 2 Malibu 2 1 28 44 4 3 7 27 2 3 0 5 2 Malibu 2 2 23 38 6 1 7 13 1 1 0 5 0 Malibu 2 3 21 36 3 2 5 22 2 3 0 5 1 Malibu 2 4 23 39 7 1 8 22 1 2 0 5 2 Malibu 2 5 24 44 3 4 7 25 2 2 0 5 1 Malibu 2 6 19 41 5 3 8 19 1 1 0 5 1 Malibu 2 7 24 38 5 2 7 19 2 3 0 5 1 Malibu 2 8 24 41 5 3 8 19 1 2 0 4 2 Malibu 2 9 20 37 4 2 6 27 1 2 0 5 1 Malibu 2 10 26 40 4 3 7 28 1 2 0 5 2


ANOVA tables for heights of Poinsettias at each nursery in Stage 2

Nursery A

SUMMARYGroups Count Sum Average VarianceColumn 1

20 598 29.9 1.778947

Column 2

20 527 26.35 4.976316

ANOVASource of Variation

SS df MS F P-value F crit

Between Groups

126.025 1 126.025 37.31165 4.04E-07 4.098169

Within Groups

128.35 38 3.377632

Total 254.375 39

SIGNIFICANTLY SHORTER THAN SPECIFICATION

Nursery B


20 598 29.9 1.778947

Column 2

20 568 28.4 7.936842



Between Groups

22.5 1 22.5 4.631636 0.037804 4.098169

Within Groups

184.6 38 4.857895

Total 207.1 39

JUSTSIGNIFICANTLY SHORTER THAN SPECIFICATION


Nursery C


20 598 29.9 1.778947

Column 2

20 503 25.15 10.34474



Between Groups

225.625 1 225.625 37.22053 4.14E-07 4.098169

Within Groups

230.35 38 6.061842

Total 455.975 39


Nursery D


20 598 29.9 1.778947

Column 2

20 475 23.75 6.302632



Between Groups

378.225 1 378.225 93.60176 8.49E-12 4.098169

Within Groups

153.55 38 4.040789

Total 531.775 39



Appendix XX - Breakdown of system costings

Ebb & Flow Floor (Recirculated)

DescriptionThe glasshouse is divided into 8 separate flood floors. Each being 25m x 19.2m. Water from a large storage tank, sufficient to hold one days flood water, is pumped into each floor, one at a time, to a depth of 3cm. Water is then drained to a sump, where it is pumped back into a storage tank via a disc and UV filter. Mains water is added to the storage tank as required. 75% of the water is reused.

EquipmentItem Quantity Cost (£) Total (£)

Leveling & constructing concrete floor (per sq.m)

3840 27.80 106752.00

Tank set (24 cu.m) 1 1200.00 1200.00Mains water refill set 1 135.00 135.00Flood set (one per two bays) 4 270.00 1080.00Sump set 1 245.00 245.00Control set 1 485.00 485.00Solenoid valve set (one per two bays) 4 75.00 300.00Linking pipework set 8 95.00 760.00Disc and UV ozone filter set 1 1400.00 1400.00

Total 112357.00

Labour Man days to install equipment 9 225.00 2025.00Total 2025.00

Maintenance over 10 yearsRepairs and renewals 10 30.00 300.00

Total 300.00

Annual Running CostsLabour (man days) 23 52.00 1196.00Water @ 34.6 litres per sq.m per week 1328640 0.61 810.47

Total 2006.47

Total costs for setting up 114382.00 28.60 per sq.m

Total costs for running 2036.47 2036.47 per annum


Ebb & Flow Floor (To waste)

DescriptionThe glasshouse is divided into 8 separate flood floors. Each being 25m x 19.2m. Water from a storage tank, sufficient to hold one days flood water, is pumped into each floor, one at a time, to a depth of 3cm. Water is then drained and run to waste.


Leveling & constructing concrete floor (per sq.m)

3840 27.80 106752.00

Tank set (24 cu.m) 1 1200.00 1200.00Mains water refill set 1 135.00 135.00Control set 1 485.00 485.00Solenoid valve set (one per two bays) 4 75.00 300.00Linking pipework set 8 95.00 760.00

Total 109632.00

Labour Man days to install equipment 7 225.00 1575.00Total 1575.00


Total 500.00


Total 4437.88

Total costs for setting up 111207.00 27.80 per m2Total costs for running 4487.88 4487.88 per

annum


Ebb & Flow Benches (Recirculated)

DescriptionThe glasshouse is fitted with mobile/static benches containing ebb and flow inserts. Each bench is 1.846m x 24m. They are supplied by water from a storage tank, sufficient to hold at least one days flood water. Water is pumped into each bench to a depth of 3cm. Water is then drained to a sump, where it is pumped back into a storage tank via a disc and UV filter. Mains water is added to the storage tank as required. 7/8th of the water is reused.


Benching (1.846m x 24m) 72 886.00 63792.00Ebb & flow inserts per sq.m 3110 14.50 45095.00Tank set 1 1200.00 1200.00Mains water refill set 1 135.00 135.00Flood set (one per two bays) 4 270.00 1080.00Sump set 1 245.00 245.00Control set 1 485.00 485.00Solenoid valve set(one per two bays) 4 75.00 300.00Linking pipework set 8 95.00 760.00Disc and UV ozone filter set 1 1400.00 1400.00

Total 114492.00

Labour Man days to install 83 225.00 18675.00Total 18675.00


Total 500.00


Total 1869.07


annum


Ebb & Flow Benches (To waste)

DescriptionThe glasshouse is fitted with mobile/static benches containing ebb and flow inserts. Eachbench is 1.846 x 24m. The benches are supplied by water from a storage tank, sufficient to hold one days flood water. Water is pumped into each bench to a depth of 3cm. Water is then drained and run to waste.


Benching (1.846m x 24m) 72 886.00 63792.00Ebb & flow inserts 3110 14.50 45095.00Tank set 1 1200.00 1200.00Mains water refill set 1 135.00 135.00Control set 1 485.00 485.00Solenoid valve set(one per two bays) 4 75.00 300.00Linking pipework set 8 95.00 760.00

Total 111767.00



Total 800.00


Total 3888.28


annum


Gantry

DescriptionWater is supplied from the mains via a storage tank. It is then piped into the glasshouse and to the ends of each bay via a 75mm pipe. Gantries running the width of the bay are then fed from these pipes through a 32mm pipe. Each gantry has its own motor, controlled from a central control system, with on, off, auto and test function. Watering can be applied on the up or down path or both. 80-degree fan nozzles are used.


PVC Pressure Pipe 10 bar 5m x 75mm

42 12.30 516.60

1 litre Saba S3 Glue 4 15.10 60.401 litre Saba cleaning fluid 1 8.90 8.90Double union valve 3 56.55 169.6575mm x 32mm x 75mm Tee Piece 24 4.98 119.52End cap 2 3.53 7.06PVC Pressure Pipe 10 bar 5m x 32mm

10 3.45 34.50

PVC Pressure Pipe 90 degree bend 32mm

24 1.30 31.20


2 5.28 10.56

Solenoid 24 40.00 960.00Gantries 24 3400.00 81600.00Track ( 25 m per bay) 600 3.00 1800.00Control System 1 2000.00 2000.00

Total 87318.39


Maintenance over 10 yearsRepairs and renewals 10 50.00 500.00Replacement nozzles 100 0.80 80.00Replacement hoses 24 40.00 960.00

Total 1540.00

Annual Running CostsLabour only 23 52.00 1196.00Water @ 14 litres per sq.m per week 2150400 0.61 1311.74

Total 2507.74


annum


Overhead

DescriptionWater is supplied into the glasshouse from a storage tank. It is run to each bay via two 75mm pipes. From these pipe each bay has 2 runs of 32mm pipe running its length. Into these 32mm pipes Dutch pin nozzles are used at 0.8-m centres.


PVC Pressure Pipe 10 bar 5m x 75mm 42 12.30 516.601 litre Saba S3 Glue 6 15.10 90.601 litre Saba cleaning fluid 1 8.90 8.90Double union valve 3 56.55 169.6575mm x 32mm x 75mm Tee Piece 24 4.98 119.52End cap 2 3.53 7.06PVC Pressure Pipe 10 bar 5m x 32mm 250 3.45 862.50PVC Pressure Pipe 90 degree bend 32mm

24 1.30 31.20


2 5.28 10.56

Dutch Pin Nozzles per 0.8m 1500 0.24 360.00Solenoid 48 40.00 1920.00Control set and electrics 1 500.00 500.00

Total 4596.59


Maintenance over 10 yearsRepairs and renewals 10 20.00 200.00Replacement nozzles 100 0.24 24.00

Total 224.00

Annual Running CostsLabour only 23 52.00 1196.00Water @ 30 litres per sq.m per week 4608000 0.61 2810.88

Total 4006.88


annum


Hand-watering

DescriptionThe glasshouse has two 75mm mains feed via cut off valves, running the length of glasshouse, situated at the central path end. A 32mm feed pipe then leads to a Geeka valve, with a single take-off per bay. A 19mm hose on reel with trigger lance is then attached and used.


PVC Pressure Pipe 10 bar 5m x 75mm 32 12.30 393.601 litre Saba S3 Glue 2 15.10 30.201 litre Saba cleaning fluid 1 8.90 8.90Double union valve 1 56.55 56.5575mm x 32mm x 75mm Tee Piece 24 4.98 119.52End cap 2 3.53 7.06PVC Pressure Pipe 10 bar 5m x 32mm 10 3.45 34.50PVC Pressure Pipe 90 degree bends 4 5.28 21.12Nickel plated ball valve 32mm 24 4.42 106.08Male coupling 32mm 24 1.14 27.36Coupling 19mm 4 1.51 6.04Jubilee clip 4 0.30 1.20Hose 50m x 19mm 2 41.00 82.00Hose guide 2 74.25 148.50Trigger lance 2 54.90 109.80Aluminium rose 2 5.10 10.20

Total 1162.63


Maintenance over 10 yearsRepairs and renewals 10 20.00 200.00Replacement lances 2 54.90 109.80Replacement roses 10 5.10 51.00

Total 360.80


Total 5467.05


annum


Capillary Matting

DescriptionThe glasshouse has two 75mm mains feed via cut off valves, running the length of glasshouse. A 32mm feed pipe then leads to a Geeka valve, with a single take-off per bay. From these Trickle Irrigation is attached. 4 lengths of 1.4 matting are used per bay. Irrigated by the trickle tape, at 0.6cm spacing. Covered with micro-porous polythene. The matting is laid on a polythene sheet.



42 12.30 516.60


2 5.28 10.56


20 3.45 69.00

Nickel plated ball valve 32mm 24 1.30 31.20Male coupling 32mm 24 0.78 18.72Polythene 80/20 3.6 x 100m 11 30.25 332.75Capillary matting 1.40m x 50m 48 74.65 3583.20Micro-perforated polythene 6 94.50 567.00Trickle tape 2 runs per mat 5 159.00 795.00Centre feed pack 24 5.45 130.80Header Pipe (25mm x 100m) 2 49.00 98.00Entry fittings (packs of 10) 24 4.80 115.20Hose 25m x 25mm 1 35.00 35.00Hose Geeka coupling 24 1.54 36.96Jubilee clips 24 0.27 6.48Punch Kit 1 12.00 12.00

Total 6708.90


Maintenance over 10 yearsReplacement Trickle every 4 years 2.5 1139.00 2847.50Replacement matting every 4 years 2.5 3583.20 8958.00Replacement micropolythene every year

10 567.00 5670.00

Replacement jubilee clips 2 0.27 0.54Replacement couplings 10 1.54 15.40

Total 17491.44


Annual Running CostsLabour only 23 52.00 1196.00Water @12 litres per sq.m per week 1843200 0.61 1124.35

Total 2320.35


annum


Drip

DescriptionTwo 75mm header mains runs the length of the glasshouse. One each end. 32mm feed to each bay leading to 10 lines of 20 x 17mm LDPE pipe. Off each pipe are 3.2 x 0.9mm capillary pipes at 30cm intervals. Pipes come pre-fitted with drip lines



42 12.30 516.60


2 5.28 10.56


20 3.45 69.00

Nickel plated ball valve 32mm 24 1.30 31.20Male coupling 32mm 24 0.78 18.72CNL units 0 4.42 0.0020 x 17mm LDPE pipe ( 250m per bay )

60 24.00 1440.00

3.2 x 0.9mm capillary tube (85cm each)

19200 0.11 2112.00

Aquastakes 19200 0.09 1728.00Total 6276.51


Maintenance over 10 yearsRepairs and renewals 10 20.00 200.00Replacement tubes 100 0.06 6.00Replacement stakes 100 0.06 6.00

Total 212.00Annual Running Costs

Labour only 23 52.00 1196.00Water @ 3.7 litres per sq.m per week 568320 0.61 346.68

Total 1542.68


annum


Trough Track

DescriptionThe glasshouse is fitted with rails (4.5m) and carriers on to which troughs (15cm x 6.2m) are fitted. 12 tracks are fitted as standard but more or less can be fitted depending on crop requirements. Troughs are supplied by water from a storage tank, sufficient to hold at least one days flood water. Water is pumped into each bench to a depth of 3cm. Water is then left until used, evaporated or run-off.


Rails, Carriers and troughs 4000 20.56 82240.00Tank set 1 1200.00 1200.00Mains water refill set 1 135.00 135.00Flood set (one per two bays) 4 270.00 1080.00Sump set 1 245.00 245.00Control set 1 485.00 485.00Solenoid valve set(one per two bays) 4 75.00 300.00Linking pipework set 8 95.00 760.00Disc and UV filter set 1 1400.00 1400.00

Total 87845.00

Labour Man days to install 83 225.00Total 18675.00

Maintenance over 10 yearsRepairs and renewals 10 50.00

Total 500.00

Annual Running CostsLabour (man days) 23 52.00 1196.00Water @ litres per sq.m per week 0.61 2061.31

Total 3257.31

Total costs for setting up 26.63 per m2Total costs for running 3307.31 per

annum


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